Another wrinkle is that 2FA is enabled and the phone number is Google Voice. If it was a non-Google phone number, substituting the nano sim onto another device would have been an easy fix.
It's likely that motherboard issue. We purchased this back in August, 2021, might still be eligible for a fix. But that won't help because I'm pretty sure that will wipe the phone. The current value of the bricked phone is that it can be used to validate her account on another device immediately so that we don't have to figure out where this mysterious ~9PM cancelation is coming from.
2FA is can definitely be annoying but I think this is more of Google support ineptitude. This is where a human should be able to step in, collect enough proof, and override immediately. If they're going to provide a link in 2 days automatically, why not one immediately?