This is your hacked iPhone on 16.3.1 iOS.

Apple is NOT going to fix this problem for you. In fact, they may have caused the problem or else they just don’t care. There is a series computer virus affecting end user devices, such as iPhones, there’s a major hack, it goes all the way into the iCloud and the apple server services as well as infecting your account, and it doesn’t matter if you back up and reset your iPhone. Apple security is breached and they are refusing to admit or fix the problem and when you contact support you get unhelpful people that tell you to take a hike.