Non-SMS 2FA, such as TOTP, FIDO - using an app like Authy or Google Authenticator or a device like Yubikey or Nitrokey or something on-device like Passkey or Apple's stuff.

There are problems with the other alternatives that can prove to be an insurmountable barrier, specially for end-user products/services.

Consider I have an app that can stitch your photos together in a panorama, and you can sign up to store your creations in the cloud for some fee.

> TOTP, FIDO, Yubikey or Nitrokey

No user is going to buy a hardware token, just for this app.

> Authy or Google Authenticator

Users are more likely to go with this, but many would still not be willing to, or simply might not understand why.

> something on-device like Passkey or Apple's stuff

I don't know about this, have never used anything like this.

Point is, SMS 2FA presents the lowest barrier to entry for most users, and it is genuinely better than having just a password. So for most applications that don't need to be super-secure, it is totally fine and probably the best solution.

I was just answering your question what are the alternatives. Didn't read to me like you were already aware of them.

I meant that there are no alternatives that are good enough to replace SMS.