Running a stalwart mail server since a few months for all my personal mails. I have auto dns configured and let stalwart handle all the dns stuff. Never had any issues. Last thing I needed to fix for perfect spam recognition: Switching from systemd resolve to unbound for dns resolution, which enables spamhouse & co. spam checking in stalwart. Before I had quit a few false-positives and false negatives. Switching to unbound fixed this.