I used a guide to setup an email server on couple of vps, and I have been running this for 7-8 years now. Adding additional features and security implementations. My servers are scoring max scores on all test I could find. Allowing me to have freedom to do with emails and domains as I wish to. And it just works. I would not change my setup for anything right now as I would see it as a downgrade.

You need to understand a lot of things but it is doable and once all is setup it just works, as long as you follow up on things like domain and certificate renewals.

I am even considering moving my mail server to my homelab… just for fun, as I still would have a backup smtp on vps.