Good News I have also tried a fresh OSX installation but the issue has not gone at all. Suddenly It fixed, maybe the last update from apple through a software update called "Command Line Tools for Xcode". Thanks to all of the Apple Devs and Frameworks Engineer who is tracking down the issue with me.

Any updates?

The same problem happens to me after updating Xcode and building a project for iMac maybe. Apple devs working on it check this : discussion

Thanks for your quick reply 👋, I try to run your given code idea still nothing changes! Which version of Xcode ? My Xcode Version 13.2.1 (13C100) Did you inspect the disgnostics ? Yes! The window message says- TimeoutError: Timed out waiting for connection to DTServiceHub after 15.0 seconds. so I generate the report check attachment. previews_diagnostics_summary.txt simctl_diagnose_log.txt Please take a look. Regards!

Big Sur kill my machine: Mac (Retina 5K, 27-inch, Late 2015) 1TB Fusion Drive is very slow safari takes too much time and the startup time is a nightmare takes 3-4 minute Xcode lagging :(