Since version 12.5, Xcode is extremely slow to do anything, build, code completion, run unit tests. Deleting the contents of ~/Library/Developer/Xcode/iOS DeviceSupport didn't fix the problem.

same here with Xcode Version 12.5 (12E262) and Big Sur 11.3.1

I've the same issue during state restoration. The CBPeripheral restored has different address compared to the peripheral used when the app is in foreground. The peripheral remains in connecting state and immediately after willRestoreState it is disconnected with error The connection has timed out unexpectedly Any workaround for this problem?