I suppose you could, but being that it's Debian based I'd say just use Debian.

Any particular reason?

Why? It's a desktop distro based on Debian. Just use Debian.

I've installed MX before, but I'm not sure why you would want to make a server out of it. I guess it's possible, but it seems to me with all the hoops you're going to have to jump through, why (not) use an OS built to be a server and be done with it?

Used it in the past, and it'sa pretty alright desktop OS. It would work as a server OS, but that's not really its main focus.

It's debian based, so might as well go for actual debian.

You can

I'd have to disagree; Proxmox is definitely the sweet spot for a self-hosting setup.