I am facing exactly the same issue Xcode 12.3 is not Responding after a few seconds I open SwiftUI project. I have extremely annoying problem with autocompletion too under SwiftUI project -> there is no autocompletion especially in viewModel files (I have to wait ~30sek to see somethig). In Xcode 12.3 I am not be able to develop my apps. Apple please do something with those issues!
iOSDev_PL
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution