NixOS in LXC works great, although I switched to bare metal NixOS a few months ago. I didn't see the need for proxmox as it hindered my ability of declaring the whole system.
Creating NixOS LXC's is a bit of a pita. Some links that helped me two years ago:
I really hate how circumventing protection measures on their own device is considered illegal. It's my device, I should be allowed to do what I want.
Even the term "protection measures" annoys me, as it tries to protect their interests on my device.
Also, linking to an emulator should not be considered "trafficking circumvention devices". Making circumvention devices illegal is bad enough.
But the streamer is an idiot too as he was publicly streaming cracked games pre release. Streaming any game can be considered copyright infringement, although it's usually not enforced (it's free advertisement).