I only ever use "sign in with" for throaway stuff I don't care enough about to register an account - if it's in any way important I setup an account, and add whatever form of 2FA I can.
I really wish 2fa was implemented in convenient form everywhere. There are ton of sites that just force me to use SMS.
I wish more supported WebAuthN - it's so much lower friction than OATH TOTP or SMS. I've got everything on 3 yubikeys (including OATH TOTP) and I feel much safer than when I just used Authy