diff --git a/src/Core/Auth/Repositories/Cosmos/Base64IdStringConverter.cs b/src/Core/Auth/Repositories/Cosmos/Base64IdStringConverter.cs
index 5ec53100f7..68ccf698f5 100644
--- a/src/Core/Auth/Repositories/Cosmos/Base64IdStringConverter.cs
+++ b/src/Core/Auth/Repositories/Cosmos/Base64IdStringConverter.cs
@@ -2,17 +2,19 @@
 using System.Text.Json.Serialization;
 using Bit.Core.Utilities;
 
+#nullable enable
+
 namespace Bit.Core.Auth.Repositories.Cosmos;
 
-public class Base64IdStringConverter : JsonConverter<string>
+public class Base64IdStringConverter : JsonConverter<string?>
 {
-    public override string Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>
+    public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>
         ToKey(reader.GetString());
 
-    public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options) =>
+    public override void Write(Utf8JsonWriter writer, string? value, JsonSerializerOptions options) =>
         writer.WriteStringValue(ToId(value));
 
-    public static string ToId(string key)
+    public static string? ToId(string? key)
     {
         if (key == null)
         {
@@ -21,7 +23,7 @@ public class Base64IdStringConverter : JsonConverter<string>
         return CoreHelpers.TransformToBase64Url(key);
     }
 
-    public static string ToKey(string id)
+    public static string? ToKey(string? id)
     {
         if (id == null)
         {
diff --git a/src/Core/Auth/Repositories/Cosmos/GrantRepository.cs b/src/Core/Auth/Repositories/Cosmos/GrantRepository.cs
index 66fc3fb792..36356f8d33 100644
--- a/src/Core/Auth/Repositories/Cosmos/GrantRepository.cs
+++ b/src/Core/Auth/Repositories/Cosmos/GrantRepository.cs
@@ -6,6 +6,8 @@ using Bit.Core.Settings;
 using Bit.Core.Utilities;
 using Microsoft.Azure.Cosmos;
 
+#nullable enable
+
 namespace Bit.Core.Auth.Repositories.Cosmos;
 
 public class GrantRepository : IGrantRepository
@@ -34,7 +36,7 @@ public class GrantRepository : IGrantRepository
         _container = _database.GetContainer("grant");
     }
 
-    public async Task<IGrant> GetByKeyAsync(string key)
+    public async Task<IGrant?> GetByKeyAsync(string key)
     {
         var id = Base64IdStringConverter.ToId(key);
         try
diff --git a/src/Core/Auth/Repositories/IAuthRequestRepository.cs b/src/Core/Auth/Repositories/IAuthRequestRepository.cs
index 6662dd15fc..3b01a452f9 100644
--- a/src/Core/Auth/Repositories/IAuthRequestRepository.cs
+++ b/src/Core/Auth/Repositories/IAuthRequestRepository.cs
@@ -1,6 +1,8 @@
 using Bit.Core.Auth.Entities;
 using Bit.Core.Auth.Models.Data;
 
+#nullable enable
+
 namespace Bit.Core.Repositories;
 
 public interface IAuthRequestRepository : IRepository<AuthRequest, Guid>
diff --git a/src/Core/Auth/Repositories/IEmergencyAccessRepository.cs b/src/Core/Auth/Repositories/IEmergencyAccessRepository.cs
index e22e934882..6edb941d32 100644
--- a/src/Core/Auth/Repositories/IEmergencyAccessRepository.cs
+++ b/src/Core/Auth/Repositories/IEmergencyAccessRepository.cs
@@ -2,6 +2,8 @@
 using Bit.Core.Auth.Models.Data;
 using Bit.Core.Auth.UserFeatures.UserKey;
 
+#nullable enable
+
 namespace Bit.Core.Repositories;
 
 public interface IEmergencyAccessRepository : IRepository<EmergencyAccess, Guid>
@@ -9,7 +11,7 @@ public interface IEmergencyAccessRepository : IRepository<EmergencyAccess, Guid>
     Task<int> GetCountByGrantorIdEmailAsync(Guid grantorId, string email, bool onlyRegisteredUsers);
     Task<ICollection<EmergencyAccessDetails>> GetManyDetailsByGrantorIdAsync(Guid grantorId);
     Task<ICollection<EmergencyAccessDetails>> GetManyDetailsByGranteeIdAsync(Guid granteeId);
-    Task<EmergencyAccessDetails> GetDetailsByIdGrantorIdAsync(Guid id, Guid grantorId);
+    Task<EmergencyAccessDetails?> GetDetailsByIdGrantorIdAsync(Guid id, Guid grantorId);
     Task<ICollection<EmergencyAccessNotify>> GetManyToNotifyAsync();
     Task<ICollection<EmergencyAccessDetails>> GetExpiredRecoveriesAsync();
 
diff --git a/src/Core/Auth/Repositories/IGrantRepository.cs b/src/Core/Auth/Repositories/IGrantRepository.cs
index 2304385be3..7ed01fadd6 100644
--- a/src/Core/Auth/Repositories/IGrantRepository.cs
+++ b/src/Core/Auth/Repositories/IGrantRepository.cs
@@ -1,10 +1,12 @@
 using Bit.Core.Auth.Models.Data;
 
+#nullable enable
+
 namespace Bit.Core.Auth.Repositories;
 
 public interface IGrantRepository
 {
-    Task<IGrant> GetByKeyAsync(string key);
+    Task<IGrant?> GetByKeyAsync(string key);
     Task<ICollection<IGrant>> GetManyAsync(string subjectId, string sessionId, string clientId, string type);
     Task SaveAsync(IGrant obj);
     Task DeleteByKeyAsync(string key);
diff --git a/src/Core/Auth/Repositories/ISsoConfigRepository.cs b/src/Core/Auth/Repositories/ISsoConfigRepository.cs
index 2ed1a15ea4..f5d6c52018 100644
--- a/src/Core/Auth/Repositories/ISsoConfigRepository.cs
+++ b/src/Core/Auth/Repositories/ISsoConfigRepository.cs
@@ -1,11 +1,13 @@
 using Bit.Core.Auth.Entities;
 using Bit.Core.Repositories;
 
+#nullable enable
+
 namespace Bit.Core.Auth.Repositories;
 
 public interface ISsoConfigRepository : IRepository<SsoConfig, long>
 {
-    Task<SsoConfig> GetByOrganizationIdAsync(Guid organizationId);
-    Task<SsoConfig> GetByIdentifierAsync(string identifier);
+    Task<SsoConfig?> GetByOrganizationIdAsync(Guid organizationId);
+    Task<SsoConfig?> GetByIdentifierAsync(string identifier);
     Task<ICollection<SsoConfig>> GetManyByRevisionNotBeforeDate(DateTime? notBefore);
 }
diff --git a/src/Core/Auth/Repositories/ISsoUserRepository.cs b/src/Core/Auth/Repositories/ISsoUserRepository.cs
index 9c97cfc94c..6691b033aa 100644
--- a/src/Core/Auth/Repositories/ISsoUserRepository.cs
+++ b/src/Core/Auth/Repositories/ISsoUserRepository.cs
@@ -1,10 +1,12 @@
 using Bit.Core.Auth.Entities;
 using Bit.Core.Repositories;
 
+#nullable enable
+
 namespace Bit.Core.Auth.Repositories;
 
 public interface ISsoUserRepository : IRepository<SsoUser, long>
 {
     Task DeleteAsync(Guid userId, Guid? organizationId);
-    Task<SsoUser> GetByUserIdOrganizationIdAsync(Guid organizationId, Guid userId);
+    Task<SsoUser?> GetByUserIdOrganizationIdAsync(Guid organizationId, Guid userId);
 }
diff --git a/src/Core/Auth/Repositories/IWebAuthnCredentialRepository.cs b/src/Core/Auth/Repositories/IWebAuthnCredentialRepository.cs
index 1fab56d07a..9a7fc88207 100644
--- a/src/Core/Auth/Repositories/IWebAuthnCredentialRepository.cs
+++ b/src/Core/Auth/Repositories/IWebAuthnCredentialRepository.cs
@@ -3,11 +3,13 @@ using Bit.Core.Auth.Models.Data;
 using Bit.Core.Auth.UserFeatures.UserKey;
 using Bit.Core.Repositories;
 
+#nullable enable
+
 namespace Bit.Core.Auth.Repositories;
 
 public interface IWebAuthnCredentialRepository : IRepository<WebAuthnCredential, Guid>
 {
-    Task<WebAuthnCredential> GetByIdAsync(Guid id, Guid userId);
+    Task<WebAuthnCredential?> GetByIdAsync(Guid id, Guid userId);
     Task<ICollection<WebAuthnCredential>> GetManyByUserIdAsync(Guid userId);
     Task<bool> UpdateAsync(WebAuthnCredential credential);
     UpdateEncryptedDataForKeyRotation UpdateKeysForRotationAsync(Guid userId, IEnumerable<WebAuthnLoginRotateKeyData> credentials);
diff --git a/src/Core/Utilities/CoreHelpers.cs b/src/Core/Utilities/CoreHelpers.cs
index 043a36c158..d900c82e24 100644
--- a/src/Core/Utilities/CoreHelpers.cs
+++ b/src/Core/Utilities/CoreHelpers.cs
@@ -388,6 +388,8 @@ public static class CoreHelpers
     /// <returns>Base64 standard formatted string</returns>
     public static string TransformFromBase64Url(string input)
     {
+        // TODO: .NET 9 Ships Base64Url in box, investigate replacing this usage with that
+        // Ref: https://github.com/dotnet/runtime/pull/102364
         var output = input;
         // 62nd char of encoding
         output = output.Replace('-', '+');
diff --git a/src/Infrastructure.Dapper/Auth/Repositories/AuthRequestRepository.cs b/src/Infrastructure.Dapper/Auth/Repositories/AuthRequestRepository.cs
index df68c06d05..db6419d389 100644
--- a/src/Infrastructure.Dapper/Auth/Repositories/AuthRequestRepository.cs
+++ b/src/Infrastructure.Dapper/Auth/Repositories/AuthRequestRepository.cs
@@ -8,6 +8,8 @@ using Bit.Infrastructure.Dapper.Repositories;
 using Dapper;
 using Microsoft.Data.SqlClient;
 
+#nullable enable
+
 namespace Bit.Infrastructure.Dapper.Auth.Repositories;
 
 public class AuthRequestRepository : Repository<AuthRequest, Guid>, IAuthRequestRepository
diff --git a/src/Infrastructure.Dapper/Auth/Repositories/EmergencyAccessRepository.cs b/src/Infrastructure.Dapper/Auth/Repositories/EmergencyAccessRepository.cs
index 195ebfadae..e6bf92bdea 100644
--- a/src/Infrastructure.Dapper/Auth/Repositories/EmergencyAccessRepository.cs
+++ b/src/Infrastructure.Dapper/Auth/Repositories/EmergencyAccessRepository.cs
@@ -9,6 +9,8 @@ using Bit.Infrastructure.Dapper.Repositories;
 using Dapper;
 using Microsoft.Data.SqlClient;
 
+#nullable enable
+
 namespace Bit.Infrastructure.Dapper.Auth.Repositories;
 
 public class EmergencyAccessRepository : Repository<EmergencyAccess, Guid>, IEmergencyAccessRepository
@@ -60,7 +62,7 @@ public class EmergencyAccessRepository : Repository<EmergencyAccess, Guid>, IEme
         }
     }
 
-    public async Task<EmergencyAccessDetails> GetDetailsByIdGrantorIdAsync(Guid id, Guid grantorId)
+    public async Task<EmergencyAccessDetails?> GetDetailsByIdGrantorIdAsync(Guid id, Guid grantorId)
     {
         using (var connection = new SqlConnection(ConnectionString))
         {
diff --git a/src/Infrastructure.Dapper/Auth/Repositories/GrantRepository.cs b/src/Infrastructure.Dapper/Auth/Repositories/GrantRepository.cs
index a12969a8fe..7389dd657b 100644
--- a/src/Infrastructure.Dapper/Auth/Repositories/GrantRepository.cs
+++ b/src/Infrastructure.Dapper/Auth/Repositories/GrantRepository.cs
@@ -7,6 +7,8 @@ using Bit.Infrastructure.Dapper.Repositories;
 using Dapper;
 using Microsoft.Data.SqlClient;
 
+#nullable enable
+
 namespace Bit.Infrastructure.Dapper.Auth.Repositories;
 
 public class GrantRepository : BaseRepository, IGrantRepository
@@ -19,7 +21,7 @@ public class GrantRepository : BaseRepository, IGrantRepository
         : base(connectionString, readOnlyConnectionString)
     { }
 
-    public async Task<IGrant> GetByKeyAsync(string key)
+    public async Task<IGrant?> GetByKeyAsync(string key)
     {
         using (var connection = new SqlConnection(ConnectionString))
         {
diff --git a/src/Infrastructure.Dapper/Auth/Repositories/SsoConfigRepository.cs b/src/Infrastructure.Dapper/Auth/Repositories/SsoConfigRepository.cs
index 0922b3a739..942ca1b3c6 100644
--- a/src/Infrastructure.Dapper/Auth/Repositories/SsoConfigRepository.cs
+++ b/src/Infrastructure.Dapper/Auth/Repositories/SsoConfigRepository.cs
@@ -6,6 +6,8 @@ using Bit.Infrastructure.Dapper.Repositories;
 using Dapper;
 using Microsoft.Data.SqlClient;
 
+#nullable enable
+
 namespace Bit.Infrastructure.Dapper.Auth.Repositories;
 
 public class SsoConfigRepository : Repository<SsoConfig, long>, ISsoConfigRepository
@@ -18,7 +20,7 @@ public class SsoConfigRepository : Repository<SsoConfig, long>, ISsoConfigReposi
         : base(connectionString, readOnlyConnectionString)
     { }
 
-    public async Task<SsoConfig> GetByOrganizationIdAsync(Guid organizationId)
+    public async Task<SsoConfig?> GetByOrganizationIdAsync(Guid organizationId)
     {
         using (var connection = new SqlConnection(ConnectionString))
         {
@@ -31,7 +33,7 @@ public class SsoConfigRepository : Repository<SsoConfig, long>, ISsoConfigReposi
         }
     }
 
-    public async Task<SsoConfig> GetByIdentifierAsync(string identifier)
+    public async Task<SsoConfig?> GetByIdentifierAsync(string identifier)
     {
         using (var connection = new SqlConnection(ConnectionString))
         {
diff --git a/src/Infrastructure.Dapper/Auth/Repositories/SsoUserRepository.cs b/src/Infrastructure.Dapper/Auth/Repositories/SsoUserRepository.cs
index a25708f7ea..99cbc25c5f 100644
--- a/src/Infrastructure.Dapper/Auth/Repositories/SsoUserRepository.cs
+++ b/src/Infrastructure.Dapper/Auth/Repositories/SsoUserRepository.cs
@@ -6,6 +6,8 @@ using Bit.Infrastructure.Dapper.Repositories;
 using Dapper;
 using Microsoft.Data.SqlClient;
 
+#nullable enable
+
 namespace Bit.Infrastructure.Dapper.Auth.Repositories;
 
 public class SsoUserRepository : Repository<SsoUser, long>, ISsoUserRepository
@@ -29,7 +31,7 @@ public class SsoUserRepository : Repository<SsoUser, long>, ISsoUserRepository
         }
     }
 
-    public async Task<SsoUser> GetByUserIdOrganizationIdAsync(Guid organizationId, Guid userId)
+    public async Task<SsoUser?> GetByUserIdOrganizationIdAsync(Guid organizationId, Guid userId)
     {
         using (var connection = new SqlConnection(ConnectionString))
         {
diff --git a/src/Infrastructure.Dapper/Auth/Repositories/WebAuthnCredentialRepository.cs b/src/Infrastructure.Dapper/Auth/Repositories/WebAuthnCredentialRepository.cs
index 85a7cc64ef..0f7e1ea1b9 100644
--- a/src/Infrastructure.Dapper/Auth/Repositories/WebAuthnCredentialRepository.cs
+++ b/src/Infrastructure.Dapper/Auth/Repositories/WebAuthnCredentialRepository.cs
@@ -9,6 +9,8 @@ using Bit.Infrastructure.Dapper.Repositories;
 using Dapper;
 using Microsoft.Data.SqlClient;
 
+#nullable enable
+
 
 namespace Bit.Infrastructure.Dapper.Auth.Repositories;
 
@@ -22,7 +24,7 @@ public class WebAuthnCredentialRepository : Repository<WebAuthnCredential, Guid>
         : base(connectionString, readOnlyConnectionString)
     { }
 
-    public async Task<WebAuthnCredential> GetByIdAsync(Guid id, Guid userId)
+    public async Task<WebAuthnCredential?> GetByIdAsync(Guid id, Guid userId)
     {
         using (var connection = new SqlConnection(ConnectionString))
         {
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/AuthRequestRepository.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/AuthRequestRepository.cs
index 11e5b3f65c..7dee40a9e6 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/AuthRequestRepository.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/AuthRequestRepository.cs
@@ -8,6 +8,8 @@ using Bit.Infrastructure.EntityFramework.Repositories;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Auth.Repositories;
 
 public class AuthRequestRepository : Repository<Core.Auth.Entities.AuthRequest, AuthRequest, Guid>, IAuthRequestRepository
@@ -25,7 +27,7 @@ public class AuthRequestRepository : Repository<Core.Auth.Entities.AuthRequest,
             var expiredRequests = await dbContext.AuthRequests
                 .Where(a => (a.Type != AuthRequestType.AdminApproval && a.CreationDate.AddSeconds(userRequestExpiration.TotalSeconds) < DateTime.UtcNow)
                     || (a.Type == AuthRequestType.AdminApproval && a.Approved != true && a.CreationDate.AddSeconds(adminRequestExpiration.TotalSeconds) < DateTime.UtcNow)
-                    || (a.Type == AuthRequestType.AdminApproval && a.Approved == true && a.ResponseDate.Value.AddSeconds(afterAdminApprovalExpiration.TotalSeconds) < DateTime.UtcNow))
+                    || (a.Type == AuthRequestType.AdminApproval && a.Approved == true && a.ResponseDate!.Value.AddSeconds(afterAdminApprovalExpiration.TotalSeconds) < DateTime.UtcNow))
                 .ToListAsync();
             dbContext.AuthRequests.RemoveRange(expiredRequests);
             return await dbContext.SaveChangesAsync();
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/EmergencyAccessRepository.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/EmergencyAccessRepository.cs
index e6a32542fb..22ca89fa0a 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/EmergencyAccessRepository.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/EmergencyAccessRepository.cs
@@ -10,6 +10,8 @@ using Microsoft.Data.SqlClient;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Auth.Repositories;
 
 public class EmergencyAccessRepository : Repository<Core.Auth.Entities.EmergencyAccess, EmergencyAccess, Guid>, IEmergencyAccessRepository
@@ -35,7 +37,7 @@ public class EmergencyAccessRepository : Repository<Core.Auth.Entities.Emergency
         await base.DeleteAsync(emergencyAccess);
     }
 
-    public async Task<EmergencyAccessDetails> GetDetailsByIdGrantorIdAsync(Guid id, Guid grantorId)
+    public async Task<EmergencyAccessDetails?> GetDetailsByIdGrantorIdAsync(Guid id, Guid grantorId)
     {
         using (var scope = ServiceScopeFactory.CreateScope())
         {
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/GrantRepository.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/GrantRepository.cs
index 09fd46835b..dd958e0c6e 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/GrantRepository.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/GrantRepository.cs
@@ -6,6 +6,8 @@ using Bit.Infrastructure.EntityFramework.Repositories;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Auth.Repositories;
 
 public class GrantRepository : BaseEntityFrameworkRepository, IGrantRepository
@@ -36,7 +38,7 @@ public class GrantRepository : BaseEntityFrameworkRepository, IGrantRepository
         }
     }
 
-    public async Task<IGrant> GetByKeyAsync(string key)
+    public async Task<IGrant?> GetByKeyAsync(string key)
     {
         using (var scope = ServiceScopeFactory.CreateScope())
         {
@@ -92,4 +94,3 @@ public class GrantRepository : BaseEntityFrameworkRepository, IGrantRepository
         }
     }
 }
-
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessDetailsViewQuery.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessDetailsViewQuery.cs
index 7ddbcc346a..d666df76cf 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessDetailsViewQuery.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessDetailsViewQuery.cs
@@ -2,6 +2,8 @@
 using Bit.Infrastructure.EntityFramework.Repositories;
 using Bit.Infrastructure.EntityFramework.Repositories.Queries;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Auth.Repositories.Queries;
 
 public class EmergencyAccessDetailsViewQuery : IQuery<EmergencyAccessDetails>
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessReadCountByGrantorIdEmailQuery.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessReadCountByGrantorIdEmailQuery.cs
index 0cdf19f2d3..a0926db576 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessReadCountByGrantorIdEmailQuery.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/Queries/EmergencyAccessReadCountByGrantorIdEmailQuery.cs
@@ -2,6 +2,8 @@
 using Bit.Infrastructure.EntityFramework.Repositories;
 using Bit.Infrastructure.EntityFramework.Repositories.Queries;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Auth.Repositories.Queries;
 
 public class EmergencyAccessReadCountByGrantorIdEmailQuery : IQuery<EmergencyAccess>
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/SsoConfigRepository.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/SsoConfigRepository.cs
index 3113f31dee..c34a024aed 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/SsoConfigRepository.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/SsoConfigRepository.cs
@@ -4,6 +4,8 @@ using Bit.Infrastructure.EntityFramework.Auth.Models;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Repositories;
 
 public class SsoConfigRepository : Repository<Core.Auth.Entities.SsoConfig, SsoConfig, long>, ISsoConfigRepository
@@ -12,7 +14,7 @@ public class SsoConfigRepository : Repository<Core.Auth.Entities.SsoConfig, SsoC
         : base(serviceScopeFactory, mapper, (DatabaseContext context) => context.SsoConfigs)
     { }
 
-    public async Task<Core.Auth.Entities.SsoConfig> GetByOrganizationIdAsync(Guid organizationId)
+    public async Task<Core.Auth.Entities.SsoConfig?> GetByOrganizationIdAsync(Guid organizationId)
     {
         using (var scope = ServiceScopeFactory.CreateScope())
         {
@@ -22,7 +24,7 @@ public class SsoConfigRepository : Repository<Core.Auth.Entities.SsoConfig, SsoC
         }
     }
 
-    public async Task<Core.Auth.Entities.SsoConfig> GetByIdentifierAsync(string identifier)
+    public async Task<Core.Auth.Entities.SsoConfig?> GetByIdentifierAsync(string identifier)
     {
 
         using (var scope = ServiceScopeFactory.CreateScope())
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/SsoUserRepository.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/SsoUserRepository.cs
index 278c5e8709..7d0152912b 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/SsoUserRepository.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/SsoUserRepository.cs
@@ -4,6 +4,8 @@ using Bit.Infrastructure.EntityFramework.Auth.Models;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Repositories;
 
 public class SsoUserRepository : Repository<Core.Auth.Entities.SsoUser, SsoUser, long>, ISsoUserRepository
@@ -17,13 +19,13 @@ public class SsoUserRepository : Repository<Core.Auth.Entities.SsoUser, SsoUser,
         using (var scope = ServiceScopeFactory.CreateScope())
         {
             var dbContext = GetDatabaseContext(scope);
-            var entity = await GetDbSet(dbContext).SingleOrDefaultAsync(su => su.UserId == userId && su.OrganizationId == organizationId);
-            dbContext.Entry(entity).State = EntityState.Deleted;
-            await dbContext.SaveChangesAsync();
+            await dbContext.SsoUsers
+                .Where(su => su.UserId == userId && su.OrganizationId == organizationId)
+                .ExecuteDeleteAsync();
         }
     }
 
-    public async Task<Core.Auth.Entities.SsoUser> GetByUserIdOrganizationIdAsync(Guid organizationId, Guid userId)
+    public async Task<Core.Auth.Entities.SsoUser?> GetByUserIdOrganizationIdAsync(Guid organizationId, Guid userId)
     {
         using (var scope = ServiceScopeFactory.CreateScope())
         {
diff --git a/src/Infrastructure.EntityFramework/Auth/Repositories/WebAuthnCredentialRepository.cs b/src/Infrastructure.EntityFramework/Auth/Repositories/WebAuthnCredentialRepository.cs
index 1499811880..b670a3f1de 100644
--- a/src/Infrastructure.EntityFramework/Auth/Repositories/WebAuthnCredentialRepository.cs
+++ b/src/Infrastructure.EntityFramework/Auth/Repositories/WebAuthnCredentialRepository.cs
@@ -7,6 +7,8 @@ using Bit.Infrastructure.EntityFramework.Repositories;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 
+#nullable enable
+
 namespace Bit.Infrastructure.EntityFramework.Auth.Repositories;
 
 public class WebAuthnCredentialRepository : Repository<Core.Auth.Entities.WebAuthnCredential, WebAuthnCredential, Guid>, IWebAuthnCredentialRepository
@@ -15,7 +17,7 @@ public class WebAuthnCredentialRepository : Repository<Core.Auth.Entities.WebAut
         : base(serviceScopeFactory, mapper, (context) => context.WebAuthnCredentials)
     { }
 
-    public async Task<Core.Auth.Entities.WebAuthnCredential> GetByIdAsync(Guid id, Guid userId)
+    public async Task<Core.Auth.Entities.WebAuthnCredential?> GetByIdAsync(Guid id, Guid userId)
     {
         using (var scope = ServiceScopeFactory.CreateScope())
         {
diff --git a/test/Api.IntegrationTest/Controllers/AccountsControllerTest.cs b/test/Api.IntegrationTest/Controllers/AccountsControllerTest.cs
index a4500046e5..1bce9398ef 100644
--- a/test/Api.IntegrationTest/Controllers/AccountsControllerTest.cs
+++ b/test/Api.IntegrationTest/Controllers/AccountsControllerTest.cs
@@ -24,6 +24,7 @@ public class AccountsControllerTest : IClassFixture<ApiApplicationFactory>
         response.EnsureSuccessStatusCode();
 
         var content = await response.Content.ReadFromJsonAsync<ProfileResponseModel>();
+        Assert.NotNull(content);
         Assert.Equal("integration-test@bitwarden.com", content.Email);
         Assert.Null(content.Name);
         Assert.False(content.EmailVerified);
diff --git a/test/Api.IntegrationTest/Helpers/LoginHelper.cs b/test/Api.IntegrationTest/Helpers/LoginHelper.cs
index f036970a09..d6ce911bd0 100644
--- a/test/Api.IntegrationTest/Helpers/LoginHelper.cs
+++ b/test/Api.IntegrationTest/Helpers/LoginHelper.cs
@@ -32,6 +32,6 @@ public class LoginHelper
         var organizationApiKeyRepository = factory.GetService<IOrganizationApiKeyRepository>();
         var apiKeys = await organizationApiKeyRepository.GetManyByOrganizationIdTypeAsync(organizationId);
         var clientId = $"organization.{organizationId}";
-        return (clientId, apiKeys.SingleOrDefault().ApiKey);
+        return (clientId, apiKeys.Single().ApiKey);
     }
 }