Oh the individual components could absolutely be ported but they won't.
Note that there's a bunch of proprietary middleware in use by games that will likely never see support on platforms other than x86_64-windows. The high-level nature of individual components doesn't mean much when some parts are just inherently unportable.
This is the reason I switched to Bitwarden.
That's cool but are the videos on Pixelfed long enough for WebP2P to work? I imagine the median video length on Pixelfed would be seconds rather than minutes as it would be on Peertube.
Nix is nothing special in that regard.
Well, with the exception that all of those tools use userns to ship almost a full userspace tree while Nix uses no containerisation whatsoever to do its job.
Mods cannot access that kind of information, only admins.
That's the thing with Nix: It works on all the distros.
Distros could of course also package it themselves (nothing preventing them from doing that) but having a baseline in Nix that you can point to makes the distro's job easier here aswell. If it works via Nix but doesn't in xyz distro's package, you know where the problem lies.
If these are local and they're botted to hell, perhaps get in contact with your instance's admins. I'm sure they don't appreciate that sort of behaviour either.
If you want anonymity, you'd use TOR, yes. If you don't need quite that level of privacy but still more than a single hop of VPN proxy, a multi-hop can have some limited benefits such as making use of multiple domicile's privacy laws.
I'd honestly just abandon the hardware. It's not worth your time to deal with that.
Based on that generic request, you're just going to get everyone's personal favourite server OS here. You'll need to give more details to get something tailored to your needs.