FaceID unavailable after disabling to help friend recover iCloud account

About 3 months ago, my friend used my iphone to try to recover her old iCloud account (she wants her old photos). She attempted to reset her account using my computer, during the process it said to continue on a trusted Apple device. She used my IPhone, it said to continue, FaceID needed to be disabled-which we did, then it told her to enter the 6 digit passcode to her old iPhone, she tried a few combinations and wasn’t successful. A message popped up on the screen saying she’d receive an email to her iCloud account with recovery instructions to continue.

Since that day my FaceID no longer works. At least 3 updates have been released since then, and I have taken EVERY step recommended by Apple to enable my faceid again, but I always get the message that “FaceId is currently unavailable….try setting up faceid again later”. My phone constantly crashes, it started acting strangely the next morning. I have chatted with support multiple times, taken it into the Genius Bar, even factory reset the phone twice. There is no damage to the camera or sensors…absolutely nothing physically wrong with the iphone…it just doesn’t work correctly now, and FaceID seems to be permanently disabled. Has anyone else ever encountered this? What should I do?