Not sure if you’ve de-googled yourself or not but there is a Google Drive Addon that has a whole slew of options for backing up your HA config. I’m sure there are alternate HA add-ons. This may require HACS but not certain.

It’s literally maintained by Fedora. Not sure why he claimed that.

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.