NixOS is a Linux distro that does a lot of things differently (for the greater good), and gaming is heavily Windows thing, which is hard to do even on conventional Linux distros (its getting better tho). That said as for your points:

1a. One of the things that would help you, is programs.nix-ld.enable = true; (for more info check https://github.com/Mic92/nix-ld , but its integrated in NixOS already)

1b. UE5 pull request has some things that might help (eg: you could just try running it with steam-run): https://github.com/NixOS/nixpkgs/issues/124963

2. Depends how you are building them, I am not a gaming developer nor tried to build a game without packaging it with Nix. But if you manage to run the UE5 I guess the procedure would be the same as long as you have all of the dependencies available for UE5

3. I am using qemu/KVM on NixOS to run games on with quite a good performance, so that should not be a problem

Software:

• firewall, no inbound and do outbound restrictions
• use immutable OS
• full disk encryption (keep in mind that in many setups you will need to be beside the computer after restart)

Hardware:

• put it in the trusted datacenter (home stuff is not safe from teenagers and people that need computer's electrical socket for a vacuum cleaner)

I cant remember anymore... Let me explain ... My first computer was with at-the-time-very-new windows xp, using primary for games, after some time it got bloated with stuff so i had to reinstall again and again over time. Then i discovered redhat,centos and debian... I started heavily distro hopping. My passion for software grew to the point that I was installing new software on daily basis, just to explore new things. But nothing seemed stable enough, ubuntu, fedora, sabayon, gentoo, arch... And their derivatives all broke under my fingers to the point that i had to do more fixing than discovering new software, I took it as a challenge and continue. At around the time of university I discovered NixOS, as with any new technology I went head on with it. It took a lot of trial and error since at the time there were no documentation for any of it. I spent months reading the code, but I never gave up, since what I have found was a gem. I found the OS that is resistant to my curiosity, I just cant seem to be able to break it. Now I use NixOS everywhere that I can, even on my work computer. I do not need to reinstall after initial installation. Well... only when hardware fails...

I knew that takos have a lot of output energy, but I did not knew that takos can power a whole car!

(I wish that someone would already posted something like this so I could just upvote it.)

I am not particularly good at math myself, but I like to program stuff... If I am any good at it... decide for yourself: https://github.com/matejc?tab=repositories ... anyway, if you have interest of doing something, stop the doubt, just do it.

In i3wm/swaywm, hyprland, ... You can assign workspaces to outputs (monitors)

Is it still necessary to reboot if you install/update/remove some system package?

What are you talking about? What nonfree programs? Can you give an example? Btw, for VPS you normally just need ssh, and that is free and even OSS.

Both have issues, just that X11 has old issues that rarely someone is workin on, while Wayland has new ones and people are fixing them. So Wayland for me, thank you.

Are you using HDMI? Try display port. (Its an old post but maybe related) https://www.reddit.com/r/swaywm/comments/w3ug4q/enabling_amds_freesync_on_sway/

Indeed, well:

• SearxNG is a meta search engine, can aggregate search results from a ton of other search engines (like DDG, Google, Bing, .... and a lot more)
• Whoogle, looks like a proxy to Google

I was a distro hopper once, then I saw the light of NixOS...