I use 1Password for this purpose essentially and I’ve printed out backup codes and put it into an emergency box. One other problem is that the MFA every other site has now with SMS means that in a disaster recovery situation one will need access to the original phone number associated with an account when logging onto for the first time on a new machine. So this means a shared voice / SMS capable account is also necessary in conjunction with e-mail to avoid more complications. I realized with Apple’s system if I lost all my gear on a trip that nobody would be able to login to my Apple account because all my devices would have been lost.

Like any backup plan, unless it’s regularly tested it should be presumed to not be working