XCode hangs when opening any project

XCode 13.4.1 on my M1 Mac Mini is always stuck when I try to open a project with it. Tried it on multiple projects but it always just shows the spinner and nothing happens. Menus don't work. There's no error message.

The command line tool xcodebuild shows some informations, the last being the two "User defaults from the command line:" and then gets stuck forever as well.

I removed XCode and reinstalled it from scratch. That didn't help. I removed everything from the ~/Library/Developer folder and reinstalled but that didn't help either. I also cleared out /Library/Developer/ and reinstalled but same results.

I already wasted two days on this and I don't understand what else I could try. Does anybody have an idea on how to fix Xcode? Do I need to format the system drive and reinstall osx from scratch?