I ran my own self-hosted email server from 2008-ish to 2018, and I would highly recommend against doing it! Especially when Fastmail and Proton are so cheap. I was running Postfix+Dovecot+Seive+SpamAssassin+Fail2ban+certbot+spf+dkim+reverse-ip+ It worked! Receiving email was overall pretty easy. I know I also did things the "hard way" by ad-hoccing all that together, and today there are a lot more out-of-the-box solu…
4 different countries, different AS.
I'm always puzzled by all the issues described by others. I had about 4 issues during these 15 years, all 4 were solved by reading the bounce message and doing what was asked in the message (contacting support of the destination).