Quite a few do require you to have at least two second-factor methods set up, although I think for me only one has ever insisted on setting up phone / text 2FA.

Quite a few do require you to have at least two second-factor methods set up, although I think for me only one has ever insisted on setting up phone / text 2FA. If you don't have a spare phone for TOTP or a Yubikey for U2F, phone-based might be all you can use (considering a surprisingly small number of 2FA supporting sites seem to implement recovery codes).