I set up a mail stack on Rocky Linux with Postfix, Dovecot, and rspamd. I don’t need a database because it’s all LDAP on the backend, and I don’t have webmail setup right now because I’m lazy. It’s a bit of a hassle to get up and running well but it’s pretty solid and I’m careful about managing my domain reputation so I don’t have any issues with my mail being delivered.
I am also trying to degoogle/debigdata my life, but it seems we’re taking radically different approaches to it. I wish you luck in your journey!