Not sure what the alternative is as most users will walk if they aren't allowed to use SMS
Sometimes the customer is not educated on safety and you have to hold a line to protect them and yourself.
Invest in good onboarding UX.
Basic security and safety should not be optional.
OIDC means your digital life is destroyed if Google ever decides to ban you. And they are well known to do so, and there is normally no recourse once you are banned. You have to be either brave or stupid to trust your security to tech giants.
Passkeys, TOTP are vulnerable to your device getting lost or broken, something that can also happen a lot.
Sadly, if you want things to work no matter what, SMS are your best bet.