I have self hosted my email since 2006. I gave up on self hosting outgoing mail in 2021, but I still keep the server up for incoming mail, and still set up throwaway accounts on there.

The hard part of hosting email is getting Google and Microsoft to accept outgoing mail. Tons of businesses that do not have visibly “outlook.com” or “gmail.com” addresses are still hosted by those servers.

I had SPF, DKIM, and a static datacenter IP address with no reputation problems. I still couldn’t get through to Microsoft, not even in people’s junk mail directory, until they manually whitelisted my address. Microsoft didn’t allow them to whitelist a whole domain. Google was a little easier, but they added new demands monthly.