Same error, and it works for me. run softwareupdate --install-rosetta and re-open Xcode.

Fine in Playing audio, error happened in Video with debug mode  [ProcessSuspension] 0x117cbea80 - ProcessAssertion: Failed to acquire RBS assertion 'WebKit Media Playback' for process with PID=18140, error: Error Domain=RBSServiceErrorDomain Code=1 "(originator doesn't have entitlement com.apple.runningboard.assertions.webkit AND originator doesn't have entitlement com.apple.multitasking.systemappassertions)" UserInfo={NSLocalizedFailureReason=(originator doesn't have entitlement com.apple.runningboard.assertions.webkit AND originator doesn't have entitlement com.apple.multitasking.systemappassertions)} without connecting Xcode ,app works fine