After self-hosting my email for twenty-three years I have thrown in the towel. The oligopoly has won.
Many companies have been trying to disrupt email by making it proprietary. So far, they have failed. Email keeps being an open protocol. Hurray?
No hurray. Email is not distributed anymore. You just cannot create another first-class node of this network.
Email is now an oligopoly, a service gatekept by a few big companies which does not follow the principles of net neutrality.
I have been self-hosting my email since I got my first broadband connection at home in 1999. I absolutely loved having a personal web+email server at home, paid extra for a static IP and a real router so people could connect from the outside. I felt like a first-class citizen of the Internet and I learned so much.