diff --git a/Emby.Server.Implementations/ApplicationHost.cs b/Emby.Server.Implementations/ApplicationHost.cs
index acabbb059b..6add7e0b39 100644
--- a/Emby.Server.Implementations/ApplicationHost.cs
+++ b/Emby.Server.Implementations/ApplicationHost.cs
@@ -109,13 +109,13 @@ namespace Emby.Server.Implementations
         /// <summary>
         /// The disposable parts.
         /// </summary>
-        private readonly ConcurrentDictionary<IDisposable, byte> _disposableParts = new();
+        private readonly ConcurrentBag<IDisposable> _disposableParts = new();
         private readonly DeviceId _deviceId;
 
         private readonly IConfiguration _startupConfig;
         private readonly IXmlSerializer _xmlSerializer;
         private readonly IStartupOptions _startupOptions;
-        private readonly IPluginManager _pluginManager;
+        private readonly PluginManager _pluginManager;
 
         private List<Type> _creatingInstances;
 
@@ -161,7 +161,7 @@ namespace Emby.Server.Implementations
                 ApplicationPaths.PluginsPath,
                 ApplicationVersion);
 
-            _disposableParts.TryAdd((PluginManager)_pluginManager, byte.MinValue);
+            _disposableParts.Add(_pluginManager);
         }
 
         /// <summary>
@@ -360,7 +360,7 @@ namespace Emby.Server.Implementations
             {
                 foreach (var part in parts.OfType<IDisposable>())
                 {
-                    _disposableParts.TryAdd(part, byte.MinValue);
+                    _disposableParts.Add(part);
                 }
             }
 
@@ -381,7 +381,7 @@ namespace Emby.Server.Implementations
             {
                 foreach (var part in parts.OfType<IDisposable>())
                 {
-                    _disposableParts.TryAdd(part, byte.MinValue);
+                    _disposableParts.Add(part);
                 }
             }
 
@@ -457,7 +457,7 @@ namespace Emby.Server.Implementations
             serviceCollection.AddSingleton<IServerConfigurationManager>(ConfigurationManager);
             serviceCollection.AddSingleton<IConfigurationManager>(ConfigurationManager);
             serviceCollection.AddSingleton<IApplicationHost>(this);
-            serviceCollection.AddSingleton(_pluginManager);
+            serviceCollection.AddSingleton<IPluginManager>(_pluginManager);
             serviceCollection.AddSingleton<IApplicationPaths>(ApplicationPaths);
 
             serviceCollection.AddSingleton<IFileSystem, ManagedFileSystem>();
@@ -965,7 +965,7 @@ namespace Emby.Server.Implementations
 
                 Logger.LogInformation("Disposing {Type}", type.Name);
 
-                foreach (var (part, _) in _disposableParts)
+                foreach (var part in _disposableParts.ToArray())
                 {
                     var partType = part.GetType();
                     if (partType == type)
diff --git a/Emby.Server.Implementations/Data/BaseSqliteRepository.cs b/Emby.Server.Implementations/Data/BaseSqliteRepository.cs
index bf079d90ca..b1c99227c3 100644
--- a/Emby.Server.Implementations/Data/BaseSqliteRepository.cs
+++ b/Emby.Server.Implementations/Data/BaseSqliteRepository.cs
@@ -186,10 +186,7 @@ namespace Emby.Server.Implementations.Data
 
         protected void CheckDisposed()
         {
-            if (_disposed)
-            {
-                throw new ObjectDisposedException(GetType().Name, "Object has been disposed and cannot be accessed.");
-            }
+            ObjectDisposedException.ThrowIf(_disposed, this);
         }
 
         /// <inheritdoc />
diff --git a/Emby.Server.Implementations/Dto/DtoService.cs b/Emby.Server.Implementations/Dto/DtoService.cs
index 5da9bea262..98eacb52b2 100644
--- a/Emby.Server.Implementations/Dto/DtoService.cs
+++ b/Emby.Server.Implementations/Dto/DtoService.cs
@@ -668,12 +668,13 @@ namespace Emby.Server.Implementations.Dto
             {
                 dto.ImageBlurHashes ??= new Dictionary<ImageType, Dictionary<string, string>>();
 
-                if (!dto.ImageBlurHashes.ContainsKey(image.Type))
+                if (!dto.ImageBlurHashes.TryGetValue(image.Type, out var value))
                 {
-                    dto.ImageBlurHashes[image.Type] = new Dictionary<string, string>();
+                    value = new Dictionary<string, string>();
+                    dto.ImageBlurHashes[image.Type] = value;
                 }
 
-                dto.ImageBlurHashes[image.Type][tag] = image.BlurHash;
+                value[tag] = image.BlurHash;
             }
 
             return tag;
diff --git a/Emby.Server.Implementations/Library/LibraryManager.cs b/Emby.Server.Implementations/Library/LibraryManager.cs
index dced6868d7..bb5cc746e9 100644
--- a/Emby.Server.Implementations/Library/LibraryManager.cs
+++ b/Emby.Server.Implementations/Library/LibraryManager.cs
@@ -461,7 +461,7 @@ namespace Emby.Server.Implementations.Library
             ReportItemRemoved(item, parent);
         }
 
-        private static IEnumerable<string> GetMetadataPaths(BaseItem item, IEnumerable<BaseItem> children)
+        private static List<string> GetMetadataPaths(BaseItem item, IEnumerable<BaseItem> children)
         {
             var list = new List<string>
             {
diff --git a/Emby.Server.Implementations/Library/ResolverHelper.cs b/Emby.Server.Implementations/Library/ResolverHelper.cs
index 7a61e2607c..52be76217e 100644
--- a/Emby.Server.Implementations/Library/ResolverHelper.cs
+++ b/Emby.Server.Implementations/Library/ResolverHelper.cs
@@ -35,7 +35,7 @@ namespace Emby.Server.Implementations.Library
 
             item.Id = libraryManager.GetNewItemId(item.Path, item.GetType());
 
-            item.IsLocked = item.Path.IndexOf("[dontfetchmeta]", StringComparison.OrdinalIgnoreCase) != -1 ||
+            item.IsLocked = item.Path.Contains("[dontfetchmeta]", StringComparison.OrdinalIgnoreCase) ||
                 item.GetParents().Any(i => i.IsLocked);
 
             // Make sure DateCreated and DateModified have values
diff --git a/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs
index 6cc04ea810..955055313e 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs
@@ -33,7 +33,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
                     return null;
                 }
 
-                if (filename.IndexOf("[boxset]", StringComparison.OrdinalIgnoreCase) != -1 || args.ContainsFileSystemEntryByName("collection.xml"))
+                if (filename.Contains("[boxset]", StringComparison.OrdinalIgnoreCase) || args.ContainsFileSystemEntryByName("collection.xml"))
                 {
                     return new BoxSet
                     {
diff --git a/Emby.Server.Implementations/Session/SessionManager.cs b/Emby.Server.Implementations/Session/SessionManager.cs
index 75945b08a2..06798628f3 100644
--- a/Emby.Server.Implementations/Session/SessionManager.cs
+++ b/Emby.Server.Implementations/Session/SessionManager.cs
@@ -159,10 +159,7 @@ namespace Emby.Server.Implementations.Session
 
         private void CheckDisposed()
         {
-            if (_disposed)
-            {
-                throw new ObjectDisposedException(GetType().Name);
-            }
+            ObjectDisposedException.ThrowIf(_disposed, this);
         }
 
         private void OnSessionStarted(SessionInfo info)
diff --git a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
index 717b53a0b6..eb375c8a25 100644
--- a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
+++ b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
@@ -1271,23 +1271,23 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             var codec = stream.Codec ?? string.Empty;
 
-            return codec.IndexOf("264", StringComparison.OrdinalIgnoreCase) != -1
-                    || codec.IndexOf("avc", StringComparison.OrdinalIgnoreCase) != -1;
+            return codec.Contains("264", StringComparison.OrdinalIgnoreCase)
+                    || codec.Contains("avc", StringComparison.OrdinalIgnoreCase);
         }
 
         public static bool IsH265(MediaStream stream)
         {
             var codec = stream.Codec ?? string.Empty;
 
-            return codec.IndexOf("265", StringComparison.OrdinalIgnoreCase) != -1
-                || codec.IndexOf("hevc", StringComparison.OrdinalIgnoreCase) != -1;
+            return codec.Contains("265", StringComparison.OrdinalIgnoreCase)
+                || codec.Contains("hevc", StringComparison.OrdinalIgnoreCase);
         }
 
         public static bool IsAAC(MediaStream stream)
         {
             var codec = stream.Codec ?? string.Empty;
 
-            return codec.IndexOf("aac", StringComparison.OrdinalIgnoreCase) != -1;
+            return codec.Contains("aac", StringComparison.OrdinalIgnoreCase);
         }
 
         public static string GetBitStreamArgs(MediaStream stream)
diff --git a/jellyfin.ruleset b/jellyfin.ruleset
index 10225e3af8..db116f46c8 100644
--- a/jellyfin.ruleset
+++ b/jellyfin.ruleset
@@ -85,6 +85,8 @@
     <Rule Id="CA1309" Action="Error" />
     <!-- error on CA1310: Specify StringComparison for correctness -->
     <Rule Id="CA1310" Action="Error" />
+    <!-- error on CA1513: Use 'ObjectDisposedException.ThrowIf' instead of explicitly throwing a new exception instance -->
+    <Rule Id="CA1513" Action="Error" />
     <!-- error on CA1725: Parameter names should match base declaration -->
     <Rule Id="CA1725" Action="Error" />
     <!-- error on CA1725: Call async methods when in an async method -->
@@ -101,6 +103,8 @@
     <Rule Id="CA1849" Action="Error" />
     <!-- error on CA1851: Possible multiple enumerations of IEnumerable collection -->
     <Rule Id="CA1851" Action="Error" />
+    <!-- error on CA1854: Prefer a 'TryGetValue' call over a Dictionary indexer access guarded by a 'ContainsKey' check to avoid double lookup -->
+    <Rule Id="CA1854" Action="Error" />
     <!-- error on CA2016: Forward the CancellationToken parameter to methods that take one
         or pass in 'CancellationToken.None' explicitly to indicate intentionally not propagating the token -->
     <Rule Id="CA2016" Action="Error" />
@@ -108,6 +112,8 @@
     <Rule Id="CA2201" Action="Error" />
     <!-- error on CA2215: Dispose methods should call base class dispose -->
     <Rule Id="CA2215" Action="Error" />
+    <!-- error on CA2249: Use 'string.Contains' instead of 'string.IndexOf' to improve readability -->
+    <Rule Id="CA2249" Action="Error" />
     <!-- error on CA2254: Template should be a static expression -->
     <Rule Id="CA2254" Action="Error" />