> You wake up in a strange place. Something happened. Everything's gone. No wallet/keys/smartphone/tablet/laptop.

at this point the _last_ thing i care about is my email.

where am i? am i ok? how are my friends/loved ones?

once those are in place, it becomes clearer how to get back to "normal"

I walk to my pc and type ssh-keygen. If i can’t do that I’ve got bigger problems. “I must be able to recover remotely using a memorised credential” is a terrible requirement.

The somewhere for password authentication is a place you have physical access. Not ssh.

PasswordAuthentication=no usually means that ssh stops directly reading /etc/passwd to authenticate, not that it stops accepting passwords completely. You'll still be able to log in with a correct password, provided KbdInteractiveAuthentication is still on, PAM is available, and the PAM policy allows for it.

The email at the root of my identity is tied to a country code domain in my country. There are robust legal processes for enforcing my status as the registrant and regaining control of it. Once I have access to that, I can use that to gain access to everything downstream.

Is it fast? No, but that's a feature.

But it does mean I get to lean on the existing processes and identity verification already part of the government bureaucracy and the courts as my backdoor.

Yeah your vault has password authentication. Your password manager in other words. Your vault is where you store your private ssh keys, and or the passwords for the keys.

I log in via console, either physical or virtual (the latter requires MFA though)

Remotely: An encrypted file with a seed / master passwords to all the other data, published under a public url you can remember, but not linked anywhere and not listed.

Locally: Same, but printed out, laminated, in a safe place with other documents.

Does this happen to you a lot? You may have other issues

A scenario where all the backups are gone and the server is somehow the only thing that survived is not a very plausible one.

1Password subscription and the memorized key. 1Password is the only place my ssh private keys are stored.