In search of self hosting email I tried out both MailInABox and Mailcow.
MailInABox wanted to control DNS records which was a no-go. The primary driver behind the project seems to have arrogant attitude towards having users do DNS records themselves. Mailcow seemed nice but was guzzling up ram for seemingly no good reason.
Finally tried out Mailu a few days ago which seems to work nice, albeit with limited testing.
Mail in a box suggests being the DNS server in an attempt to be more user friendly, there are a lot of DNS records to setup for mail. How ever external DNS is supported (see "System status & DNS" in https://mailinabox.email/guide.html)