I had to manage email infrastructure for years as part of my job and I really don't see how running your own email server can be a good idea for anyone. Setting it up superficially might be a quick and easy task but maintaining it stable takes hell of a lot of effort. I seriously cringe every time I see this type of guide and articles, it just makes me think that people who write them have zero experience running a mail server and have no idea what it takes to set up one that is secure and stable.

For majority of people best middle ground is to buy a cheap domain and a cheap cPanel/web hosting and just use that to host emails. You'll be done in 5min, it will cost you a cup of coffee and you won't have the headache maintaining anything other than passwords.