Well folks, it certainly seems like hosting both email and mail server on the same VPS is possible.

The trouble I'm having is that, because I'm not terribly well clued in about mail server admin, I really need a step-by-step tutorial to make setting it up a realistic possibility, but... thusfar I've been unable to really find such a thing.

What I have found are plenty of guides for setting up a standalone mailserver, and so I'm looking at the daunting task of modifying what they tell me to do, while still managing to serve my websites.

At the moment, my biggest hurdle is I keep coming up against:

sudo hostnamectl set-hostname mail.your-domain.com

-- correct me if I'm wrong, but this is going to change my hostname so that I no longer have a hostname for web?

Seems I need an FQDM for hosting a mail server, but at the same time I also need an FQDM for serving websites.

How do I do both? I'm running Apache2 if that helps...

Thanks -- mailcow looks good.

What I'm struggling to find good info on is how to get a web server (based on apache2) and mailcow (based on ngix/docker) running happily alongside.

I'm no expert but I do understand the web server side of things.

I had a go with iRedMail via this tutorial: https://www.linuxbabe.com/mail-server/email-server-debian-11-iredmail

^^ but that hijacked my whole server so it became just a mail server and stopped serving web. It's a shame because the tutorial was pretty comprehensive and just the sort of thing I need!