while it will not give your such configuration precision, i highly recommend to checkout sovereign project - https://github.com/sovereign/sovereign

In the beginning I used to setup just personal "cloud", but now actually using it to send emails for other businesses I run.

In theory it should be possible to run these playbooks without all extras and just keep bare minimum to send emails (never tried it, so not sure what it will take)

Sovereign will configure postfix + dkim + spf + blacklists for you. Plus provides your imap mailboxes to receive bounces and regular mail.