Same issues here. The problem seems solved itself by reinstalling xcode, but somehow it appear again. Unfortunately all replies claiming resolved the problem are all pretty vague in this thread. The MacOSX12.3.sdk folder exists in Mac finder, but it’s a link.
Here’s my messages:
Showing All Issues
[2976/5282] Link UnrealEditor-UnrealEd.dylib
clang: error: no such file or directory: '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk
2022-08-25 08:53:46.994 xcodebuild[69276:213744] Requested but did not find extension point with identifier Xcode.IDEKit.ExtensionSentinelHostApplications for extension Xcode.DebuggerFoundation.AppExtensionHosts.watchOS of plug-in com.apple.dt.IDEWatchSupportCore
2022-08-25 08:53:46.994 xcodebuild[69276:213744] Requested but did not find extension point with identifier Xcode.IDEKit.ExtensionPointIdentifierToBundleIdentifier for extension Xcode.DebuggerFoundation.AppExtensionToBundleIdentifierMap.watchOS of plug-in com.apple.dt.IDEWatchSupportCore
2022-08-25 08:53:47.507 xcodebuild[69278:213777] Requested but did not find extension point with identifier Xcode.IDEKit.ExtensionSentinelHostApplications for extension Xcode.DebuggerFoundation.AppExtensionHosts.watchOS of plug-in com.apple.dt.IDEWatchSupportCore
2022-08-25 08:53:47.507 xcodebuild[69278:213777] Requested but did not find extension point with identifier Xcode.IDEKit.ExtensionPointIdentifierToBundleIdentifier for extension Xcode.DebuggerFoundation.AppExtensionToBundleIdentifierMap.watchOS of plug-in com.apple.dt.IDEWatchSupportCore/System/Library/PrivateFrameworks/MultitouchSupport.framework/Versions/Current/MultitouchSupport.tbd’
Edit: It resolved by cleaning the “Derived Data” folder for xcode (File->Workspace settings), and I also regenerated project file, not sure if it helps. Shame on Apple for such painful development experiences.