Almost all multiplayer games work even with anti-cheat. The once that do not use kernel level root kits for anti cheat. Vanguard is even worse then a normal root kit as it forces it self to be loaded with the OS.
No need for money. Many people will glady help you 😁.
Anyway I have not modded skyrim yet. But a easy way to mod on Linux I found is copy the installed game including mods over from windows where you did mod the game. Works for quite a few games. If you can't get it working directly from Linux that is.
A few things you have to learn in general are Virtualization docker and some network management. You can do this on very old stuff. And when you know the basics you can make a better guess to what hardware you need for the things you want.
I love and hate unifi at the same time. Their single web management for all devices is super convenient but some advanced things are a nono. It is expensive for what it is.
No, dont run server. Many programs will not allow to be installed on it without getting enterprise versions of the software. Also gaming on it can have many limitations.
Sounds like some weird 3D movie or something?