I have the same issue. iPhone 7, worked great with iOS 14 but I 'upgraded' to iOS 15.4 and also upgraded Xcode to 13.3 and I just get an endless 'waiting' message for the phone. I have rebooted everything, reinstalled iOS on the phone several times, nothing has helped. (It sure would be nice if Apple had a way for us to install old version of iOS on a device. Not everyone can afford to leave a dev phone on an old OS release when so many new releases come out. Then I could have fixed this problem in an hour instead of wasting the better part of an day on it.)