Big Sur 11.5.2, got same issue. rvictl -s UUID always [FAILED]. Installed MobileDeviceDevelopment.pkg manually, executed rvictl -s UUID - it [FAILED] again, but this time system alert that asked me for permissions. System Preferences --> Security & Privacy --> Allow --> Restart. Now [SUCCEEDED]. It works, but for some reason interface is closed in few seconds.
UPD: after second restart RVI works as expected.