EDIT: You know, after some time to cool off, Google Authenticator 2FA can still be enabled and isn’t being phased out like the less secure SMS 2FA, so it’s really not the end of the world here. The chance of permanent lockout is avoided, even if the whole Google Prompt system is still wack.
I guess if you’re locked up like OP, you’re basically fucked, right?
Probably. Wouldn’t be surprised if you were equally fucked with Microsoft as well. Faceless tech companies without useful customer support are hell to recover access to. The most reliable way to get any kind of action taken on your behalf is to go through their legal team.
You can also try to make a thread on Orange Reddit where a lot of Googlers/Applers/Microsofters tend to hang out. The process is 1) write a clear blog post with tons of screenshots and submit it 2) get lucky enough to reach the front page 3) gather enough outrage that the comments start complaining about big tech 4) hope that someone over at Google notices and reaches out to you. Also works with Stripe and Cloudflare!