Anyway, my own devices are the biggest risk in my threat model. Both my laptop (where I'd store the backup codes for GH MFA) and my phone (normal MFA authenticator app) turning into bricks is a WAY higher risk than someone stealing my Github password.
I'm not even a part of any orgs, no maintained packages (not on the account I use now, anyways). So I could store my backup codes on the cloud, but Google is getting fussier every day about 'lack of backup device' or whatever.
I could use a one time pad (and just memorize it), and store the encrypted backup codes on some kind of decentralized, permanent db. So a blockchain. But that costs money, and this is basically a venial irrelevant problem that I'm only complaining about to be a naysayer on this thread. So let's look for a free solution...
Well, what about... free anonymous blogging solutions! I can publish it to a bunch of these. I can use memorable usernames. Now, I just have to remember the platform(s, plural, cause one platform is still risky, could get the account banned or something by doing this, so I'll want to use all the big ones, reddit, twitter, and so on), the usernames (which will all be the same, to accommodate memorization lol), the 2fa backup code one time pad, and of course the password itself. But I could use the password as the one time pad to lighten the load. And the username could be really easily made memorable.
Yes! How easy is that? Okay, I'm going to try it out. If my approach is flawed, feel free to steal my GH account (as you can probably ascertain, it's a throwaway GH account, which is the only reason I'd be annoyed at having to 2FA for it).
I'll report back to this threat and leave a response to myself once I have this set up, in case anyone else is curious.