I self-hosted my email during some years. My IP was banned in certain providers a few times, I guess due to neighbors. I also found quite complex to manage the service using dovecot at that time, but I guess today we have simpler servers.

However, I ended up moving away. Sadly, dealing with deny-lists and the management overhead was not worth for me. Fortunately, there are alternatives that doesn't require you to go to big providers :)