Unable to reset Macbook Password - error connecting to Apple ID server

Hi there. My son has forgotten the password for his Macbook. I think it's running Ventura but I'm not sure.

I've gone through the password recovery process. It asks for an Apple ID. I enter his Apple ID, which I'm sure is correct as I can log in with it on the machine I'm on now, and it says "There was an error connecting to the Apple ID server"

However, it doesn't seem to be a connectivity thing, as if I try and log in with my Apple ID and password it gives me the two factor prompt and I get the verification code on my other Macbook (which means it must have a connection) and then my son's machine shows a message saying "The supplied iCloud account was unable to unlock this volume".

I saw a message about booting into recovery mode (apple+r) and using the terminal utility to run "resetpassword" but I can't launch terminal as it asks for an administrator password (and my son has the only account on the machine).

I don't mind nuking the machine and starting over as the data isn't important but it doesn't seem I can do anything without the user account password for the machine.

Any ideas? Thanks