It's a bug with dyld. https://developer.apple.com/forums/thread/679098 Apple, pay attention on this. We can't debug in Xcode.

Same trouble on OSx 11.3.1 Xcode 12.2 (12B45b) on Simulator with iOS 14.2 Apple, please fix this bug. It restricts debugging during development. it's critical issue.

@_whatthedeuce It doesn't help unfortunately. Still have trouble with attaching debugger and slow running time.