I also got the error -[MTLDebugDevice newLibraryWithURL:error:]:2250: failed assertion `url must not be nil.' My version of Xcode is 14.3, I used Simulator iOS 16.2. The error went away when I started using Simulator iOS 16.4.

The issue is still unresolved (Xcode 14.2) and is preventing us from making a good interface.