More elaboration on what’s involved in “correctly” would probably drive the point home — “this works because” vs “works for me.”

I made sure to include the word correctly in the reply. Mox mailserver tells you exactly what to do. I think mailcow does as well. A lot of people don't do it and then tell others that selfhosting email with good deliverability is impossible. You set it up once and you're good to go