Any 2FA is inherently susceptible to losing one of the factors. It's designed to deny access when only one factor is present, so this is kind of a feature not a bug, and part of the security-vs-convenience tradeoff. Do you have any specific reason to think SMS 2FA in particular is a terrible idea?

Not if you have a password-protected Yubikey with GPG/RSA signing, encryption, and authentication keys and a second backup Yubikey with the same keys. If you lose one, order two more ASAP, use the backup key to change your keys in every machine and revoke that key (thereby rendering the lost Yubikey and your backup useless). Wait for the new Yubikeys to arrive, generate new keys, change all machines to these new keys, and revoke the temporary keys you generated.

For 2FA specifically, SMS is weak because of its vulnerability to SIM swap attacks[0]. There's been a few reported incidents where attackers stole cryptocurrency from accounts protected by SMS 2FA[1].

[0]: https://en.wikipedia.org/wiki/SIM_swap_scam

[1]: https://btcmanager.com/sim-swap-attacks-amplify-companies-re...

I actually agree with you. Aside from apps that don't offer anything other than SMS 2FA, I always opt for TOTP-based 2FA. However, one compromise I've made is with Authy: they back up your saved config, but you must SMS verify (or have it installed on a 2nd device to verify a new device)

If you're comfortable with a paid option, consider StandardNotes' TokenVault: https://standardnotes.org/extensions/tokenvault