diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5e63c62c66..8f432b77bb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,23 +1,10 @@
 ########################################
 # General setup
 #
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.20...4.2.1)
 
-cmake_policy(SET CMP0079 NEW) # let target_link_libraries() link to a target defined in a different directory
 cmake_policy(SET CMP0080 OLD) # allow using BundleUtilities at configure time
 
-if (POLICY CMP0099)
-  cmake_policy(SET CMP0099 NEW) # Propagate INTERFACE_LINK_OPTIONS from private dependencies, used by MacOS framework builds of SDL
-endif()
-
-# Weird chicken-and-egg problem: We can't check the compiler before the project() call, but we have to set the policies before it.
-# So we do this in two steps: Set the policies if they exist, then error out afterwards if we end up being MSVC and they don't exist.
-if (POLICY CMP0117)
-  cmake_policy(SET CMP0091 NEW) # MSVC runtime library flags are selected by an abstraction.
-  cmake_policy(SET CMP0092 NEW) # MSVC warning flags are not in CMAKE_{C,CXX}_FLAGS by default.
-  cmake_policy(SET CMP0117 NEW) # MSVC RTTI flag will not be added by default.
-endif()
-
 if (POLICY CMP0141)
   cmake_policy(SET CMP0141 NEW) # MSVC debug information format flags are selected by an abstraction.
 endif()
@@ -28,6 +15,12 @@ set(CMAKE_OSX_DEPLOYMENT_TARGET "11.0.0" CACHE STRING "")
 
 set(CMAKE_USER_MAKE_RULES_OVERRIDE "${CMAKE_CURRENT_SOURCE_DIR}/CMake/FlagsOverride.cmake")
 
+# CMake 3.28 and later scan c++ source files for module imports by default. Since we don't use
+# modules scanning is pointless, so disable it. This also prevents Clang from generating an error
+# if the clang-scan-deps tool isn't installed:
+# "CMAKE_CXX_COMPILER_CLANG_SCAN_DEPS-NOTFOUND: not found".
+set(CMAKE_CXX_SCAN_FOR_MODULES OFF)
+
 project(dolphin-emu)
 
 if (CMAKE_VERSION VERSION_LESS "3.25" AND CMAKE_SYSTEM_NAME MATCHES "Linux")
@@ -35,12 +28,6 @@ if (CMAKE_VERSION VERSION_LESS "3.25" AND CMAKE_SYSTEM_NAME MATCHES "Linux")
 endif()
 
 if (MSVC)
-  if (POLICY CMP0117)
-    # cmake is a weird language. You can't do if(not POLICY)
-  else()
-    message(FATAL_ERROR "Please update to CMake 3.20 or higher.")
-  endif()
-
   set(CMAKE_C_STANDARD 99)
   set(CMAKE_CXX_STANDARD 23)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index 8d74b60470..c98a9b3188 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -16,7 +16,7 @@ if(CMAKE_SYSTEM_NAME MATCHES "Windows")
 endif()
 
 if (NOT MSVC)
-  set(CMAKE_CXX_STANDARD 20)
+  set(CMAKE_CXX_STANDARD 23)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
   set(CMAKE_CXX_EXTENSIONS OFF)
 endif()
diff --git a/Source/Core/DiscIO/VolumeFileBlobReader.cpp b/Source/Core/DiscIO/VolumeFileBlobReader.cpp
index 7cbc06e589..92eb9b4ae2 100644
--- a/Source/Core/DiscIO/VolumeFileBlobReader.cpp
+++ b/Source/Core/DiscIO/VolumeFileBlobReader.cpp
@@ -33,6 +33,11 @@ VolumeFileBlobReader::VolumeFileBlobReader(const Volume& volume, const Partition
 {
 }
 
+// This is defined here instead of the header so that the definition of FileInfo is visible when
+// m_file_info is destroyed, preventing a compile error caused by calling unique_ptr's destructor
+// with an incomplete type.
+VolumeFileBlobReader::~VolumeFileBlobReader() = default;
+
 std::unique_ptr<BlobReader> VolumeFileBlobReader::CopyReader() const
 {
   ASSERT_MSG(DISCIO, false, "Unimplemented");
diff --git a/Source/Core/DiscIO/VolumeFileBlobReader.h b/Source/Core/DiscIO/VolumeFileBlobReader.h
index 58d349a0d4..49fe4cd200 100644
--- a/Source/Core/DiscIO/VolumeFileBlobReader.h
+++ b/Source/Core/DiscIO/VolumeFileBlobReader.h
@@ -20,6 +20,7 @@ class VolumeFileBlobReader final : public BlobReader
 public:
   static std::unique_ptr<VolumeFileBlobReader>
   Create(const Volume& volume, const Partition& partition, std::string_view file_path);
+  ~VolumeFileBlobReader();
 
   BlobType GetBlobType() const override { return BlobType::PLAIN; }
   std::unique_ptr<BlobReader> CopyReader() const override;
diff --git a/Source/Core/DolphinQt/CMakeLists.txt b/Source/Core/DolphinQt/CMakeLists.txt
index cd49f7f108..1960e944bd 100644
--- a/Source/Core/DolphinQt/CMakeLists.txt
+++ b/Source/Core/DolphinQt/CMakeLists.txt
@@ -1,8 +1,3 @@
-if(POLICY CMP0084)
-  # Disable trying to search for Qt3/4 if what we actually want is not found
-  cmake_policy(SET CMP0084 NEW)
-endif()
-
 if (MSVC)
   if(_M_ARM_64)
     list(APPEND CMAKE_PREFIX_PATH "${CMAKE_SOURCE_DIR}/Externals/Qt/Qt6.5.1/ARM64")
diff --git a/Source/Core/VideoBackends/Metal/MTLObjectCache.mm b/Source/Core/VideoBackends/Metal/MTLObjectCache.mm
index c4ecfc0713..7dce7a0f34 100644
--- a/Source/Core/VideoBackends/Metal/MTLObjectCache.mm
+++ b/Source/Core/VideoBackends/Metal/MTLObjectCache.mm
@@ -27,16 +27,6 @@ std::unique_ptr<Metal::ObjectCache> Metal::g_object_cache;
 static void SetupDepthStencil(
     MRCOwned<id<MTLDepthStencilState>> (&dss)[Metal::DepthStencilSelector::N_VALUES]);
 
-Metal::ObjectCache::ObjectCache()
-{
-  m_internal = std::make_unique<Internal>();
-  SetupDepthStencil(m_dss);
-}
-
-Metal::ObjectCache::~ObjectCache()
-{
-}
-
 void Metal::ObjectCache::Initialize(MRCOwned<id<MTLDevice>> device)
 {
   g_device = std::move(device);
@@ -554,6 +544,17 @@ public:
   }
 };
 
+Metal::ObjectCache::ObjectCache()
+{
+  m_internal = std::make_unique<Internal>();
+  SetupDepthStencil(m_dss);
+}
+
+// This is defined here instead of the header so that the definition of Internal is visible when
+// m_internal is destroyed, preventing a compile error caused by calling unique_ptr's destructor
+// with an incomplete type.
+Metal::ObjectCache::~ObjectCache() = default;
+
 std::unique_ptr<AbstractPipeline>
 Metal::ObjectCache::CreatePipeline(const AbstractPipelineConfig& config)
 {