I'm having this issue with Xcode 12.2 again. Widget in Testflight build can not work for some devices (14.2.x). The two issues "Dead Code Stripping", and disable "Bitcode" were solved by Apple and mentioned in Xcode 12 release note. But I'm not sure if Xcode 12.x has the issue again, or just an iOS version bug? (Reboot the phone make Widget works again, but got down after awhile again)