All these..... I am not self hosting at home though... I am using a Conatabo VPS.... The vid you linked seems helpful too
https://tonyteaches.tech/mailcow-self-hosted-email-server/
https://docs.mailcow.email/getstarted/prerequisite-dns/#references
How to set Reverse DNS (rDNS/PTR record) in Contabo server https://youtu.be/clPJqoIxCjs

https://maps.gardiol.org/ Dang Willy you travel a lot. Thanks for the share.