Not if you want your emails to be reliably delivered. Even if you set up all of the right things and follow all of the rules, you will probably always be fighting to stay out of the spam folder.

https://cfenollosa.com/blog/after-self-hosting-my-email-for-twenty-three-years-i-have-thrown-in-the-towel-the-oligopoly-has-won.html

Convenience rarely comes with security and/or resilience. TOTP is about having two separate parts of the auth process so that compromise of one is protected by the other. Don’t keep them in the same place.