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.

regress with old bugs

Have it write a test suite that enforces the correct behavior, and tell it that the test suite must pass after any change. Make sure it’s not cheating (return true) inside the test suite.

3 weeks is fine. Add stabilizer now. It will be fine in a vehicle.