[tqwhite]

I have run https://mailinabox.email (Ubuntu, Digital Ocean) for six or seven years. It is astonishingly simple to install and operate. I have never found an email feature (webmail, calendar) or security requirement (DNSSec, etc) that is not already built in. I go months, maybe even a year without doing anything to it.

It also is a DNS server. That is a surprisingly nice thing to have. It provides an API that makes a nice integration with LetsEncrypt for non-website certificates.

It's a 100% good thing if you are a technical type and do not want a corporation governing your email.

[jmconfuzeus]

It's also good. There's also mailcow that provides a containerized solution.

Running your own mail server is not hard at all.