It sounds like the mistake here is not appointing another Super Admin, and making sure they don't use their account for day to day needs. Or just having two Super Admin accounts controlled by the same person, heh.
I can't see how not using one's Super Admin account wouldn't prevent tripping some kind of fraud lockout that's impossible to recover from.
Randomly, I just remembered that I lost a GCP account because I tried logging in from Laos, and they asked me for the front and back photos of a payment card that I used ages ago that I didn't bother making scans of before it was lost. Urgh.
It doesn't address this thread's concern that a single Super Admin could be locked out with no recourse, since Google's customer support is horrendously bad.
I don’t love it either, but these are Google’s published best practices / recommendations