Since Microsoft bought Github, I have to use a one-time key every time I log in, which is annoying. But today I received a letter in which they insist that I have the second of two factors from the list:
Security key
GitHub Mobile
Authenticator application (TOTP)
Text messages (SMS)
I don't use smartphones, so all I can do is share my phone number, which will naturally be passed on to spammers. Tell me an alternative to GitHub, please.
But 50% of the 2FA options you listed do not require a mobile device. Security key and TOTP app. TOTP apps are free. Try authy.