I don't, sorry. The short story is that I use Docker Mailserver [0] with some customised config for SMTP relaying, spam filtering and Gmail fetching with spam filtering. I also have a Roundcube container.

Underneath though, it's a pretty standard Postfix + Dovecot setup and there are plenty of those around.

[0]: https://docker-mailserver.github.io/docker-mailserver/latest...