About the first part of your post, actually there is a single package for all the components: mailu does that in the form of a set of docker images. I've also heard about iRedMail but I don't know it. For the rest of your comment you're right, after launching mailu you still have to configure the DNS and deal with some providers still thinking you're a spammer. But at least you can avoid the painful traditional setup which requires to install multiple pieces of software and configure them to make them talk each other, and mailu also helps you with DNS by telling you which value you should put to have dkim working (and maybe also something else that I'm not recalling right now). Personally the problem that stopped me from having my own mail server was the difficulty to have a reverse PTR record configured for your vps. I was trying to get it with an Oracle Cloud server, but after a rather time consuming process of trying to gather information about this, I found out that Oracle didn't offer the option to have a reverse PTR record.