Pixel 7 won't unlock

[kasg]

This is a copy of a question I posted on the Google support forum:

"Hi, my phone restarted overnight, maybe a software update I don't know. I entered my SIM PIN, fine. I entered my unlock PIN, which was accepted, but all it does is go back to the lock state and I have to enter it again, and again, and so on, but it never unlocks. I have tried restarting in Safe Mode, which made no difference. I have tried Rescue Mode but I can't connect to the phone to do anything because it says my software is too late a version. Find My Device finds the phone and will play a sound but there's not much else I can do other than a factory reset, which I'd rather avoid. About the only thing I can do with the phone is receive calls. It's using Nova Launcher, if that makes any difference. Any suggestions? Thanks."

The official response, and the one I got while chatting with a support rep, was to do a hard reset. I cannot believe this is the only option, the phone was working absolutely perfectly before this happened and it still is, after a fashion, e.g. it still connects to the Wi-Fi, it still sounds alarms, I just can't use it!