Unless you’re a seasoned sysadmin, hosting your own mail server is going to be more trouble that it’s worth. It’s a lot of work, and when that was a common thing (companies having their own mail servers) usually they had dedicated admin teams (when they bothered hiring more than one admin, that is) to run it. It’s a lot of work.
I migrated my domain over to Protonmail a couple of years back, and it’s the best money I’ve spent in a long time.