iCloud Keychain is already a better-than-1Password 1Password-lite and 2FA itself for your Apple id is built into iOS and macOS. I think the limiting thing there is desktop Safari - you don't really notice the full integration unless you're using Safari on macOS as well.
Apple has had mandatory device-based 2FA for a while now, but it only works for iCloud logins.
Yes, super annoying. Now I can no longer get into my Apple Developer account without walking to my development mac I use to run xcode builds (for a react native app), since for some bizarre reason the only 2FA they support is their own which requires Apple hardware.
It's bad enough their development toolchain requires you to buy their hardware, now to log into their websites you also have to buy their expensive hardware.
Apple continues to support SMS as 2FA. It is a bit hidden when signing in.
In fact, Apple should redesign Keychain into a user friendly, 1Password-lite product with 2FA built-in (1Password offers this too) or as a separate app that works with Keychain.