I belive its secure because until now noone found an exploit in multiplayer games with anti-cheats yet and used it to install cheats during the finals of an E-Sports tornament or something.

There are various ways to mask your hardware. For example its close to trivial to change your MAC-Address.

I would also consider to set up a DMZ for the Hypervisor and maybe NAS (depends on how you use it) if you access it from the internet.

You know zsh has fuzzy completion. There are also plenty of fuzzy finder out there which do just that.

I dont know what you mean? The Nextcloud app works perfectly for me.

Probably.