Now, with version 14.2 the issue is still not solved.

I finally uninstalled and reinstalled Xcode - the issue still exists. Seems, we have to wait (and hope) for the next update. ...

Thank you for your suggestion, AnatolyMazkun. I checked Agreements and Guidelines for Apple Developers, however there were no pending agreements.

I agree, geezerbuttz. I really don‘t feel like I want to develop in the Swift / Xcode universe. A message that doesn‘t help at all and no hint about what to do. Not even a „we‘re working on it“. Apparently Apple thinks their products are so fancy - they’re just flawless. Well, I rather leave it than love it.