Selfhosted

don't go with server variants of the OS. they are intended for boxes that work without display and keyboard, which you have. instead, install any normal distro you're familiar with. it's infinitely easier to fix something with the full GUI at your disposal.

this is just your first install, you will iterate, and through that process you'll get better and leaner, in terms of underlying OS. think of it as training wheels on a bike, you'll pull them off eventually.

wired connection only, leave wireless turned off, and assign it a static IP address.

don't do containerS, do one container first. figure out where you're gonna store the compose files, where it will store data, how you will back that data up, etc. then add another. does it fit into your setup? do you need to modify something? rinse. repeat.

casaOS, aside from it's murky background (some chinese startup or sumsuch, forgot?) doesn't provide that path forward nor allows you to learn something, too much hand holding.

good luck.