[layer8]

> Be prepared to spend at least $50/mo and at least 6 hours in setup and 1-2 hours a month debugging if you do it personally. […] Unlike some people are saying, you should never do this off a VPS if you have an interest in keeping the email secure and functioning for a long time.

That’s simply not true in that generality. I run my mail server on a VPS costing ~$7 per month (have been for ~20 years, switching the VPS provider once in that time) and mostly only have to do something when I major-upgrade Debian every 2-3 years. (Security updates are automated.) Some of my friends do the same. For the initial setup I would plan for more than 6 hours, it can certainly take some effort to work through all the details.