That’s all fine and dandy until your IP address and/or email address gets blacklisted. Hosting the server is the easy part. Properly dealing with anti-spam measures so you don’t get flagged as a spammer or scammer is the hard part. And before you think that’s unlikely, one of the ways of getting flagged is to run an email service on a consumer ISP network (e.g. comcast).
Helm used to be one such service. They hosted the IP address and smtp gateway, but you hosted the actual email server. They had no data to hand over; it was in your home. Unfortunately, their service went offline last year.
I hate to admit it but I’m all-in on google, for mail, drive, calendar, meet/chat, Android, oauth. It’s all too convenient.
I have one personal account, one per long-term client/employer (w/their service), and one garbage (for sign-ups and low-priority web accounts). I often use the user+purpose@gmail.com pattern for creating special-purpose temporary addresses. We use sendgrid for sending user emails.
Fine, don’t believe someone that’s done it before. Google “why you shouldn’t host your own email server” and research before you say anything else.