I’ve been running mailcow for almost 2 years with no issues. I’m not doing anything major with it, mainly using it to send myself alerts on the environment, but it does work for external purposes if I want it to as well. Updating is easy and seamless. I did get greylisted almost immediately though, so I use SMTP2Go and it works great as a free relay for the amount of mail I generate.
It’s literally maintained by Fedora. Not sure why he claimed that.