I also self host a mail server but I don’t think I’d every put anything super important through it. Right now I use it to send emails from the services I run (plex, file sharing, etc). It’s a fun little project but if you want something reliable it’s going to get pricy very quick.
I’ve never used SolarWinds patch manager, but after all of those breaches I’m very leery on any of their stuff. Another option to look into is manage engine patch manager plus. It can be a bit of a pain but it worked decently enough. Also, very cheap. Just don’t expect a super robust and deliable program