Yes, that was the situation for me exactly, that basically if I lose or break my phone, I obviously have other devices that can access 1Password and my email, but I'm locked out of anything that requires SMS or an authenticator app to 2FA.

Definitely made me feel that at the very least I should be getting a yubikey so that I can have authenticator codes across multiple devices.

Back when eSIM was relatively new, while upgrading to a newer iPhone, my wife’s eSIM didn’t get transferred over but still got deactivated on the old phone.

And the T-Mobile Germany portal to download a new eSIM required authentication via SMS to that now deactivated number. That was fun. (As they didn’t have an alternative procedures to provision eSIMs in place, we had to go visit a store to get a new physical SIM first and could then convert that to eSIM.)