My experience has been in complete agreement with yours: I love the theory, but the practice is so, so painful.
And yes, I also had to settle for your NVIDIA fix. I suspect I would have had a marginally better time on Arch as there are more people beating their heads against it and documenting how they made it work. NixOS documentation is piss-poor in comparison.
I don't know how to adapt those settings to the corresponding module - there are often differences in naming and hierarchy conventions - and there are other NixOS-specific considerations with regards to its shared-nothing architecture.
While it is technically possible to adapt the information in the Arch wiki to NixOS, you need a strong understanding of the software, how it was packaged for NixOS, and NixOS itself to do it effectively. Once you do figure it out, it's pretty straightforward, but that can be hours as opposed to minutes with Arch.
Modern modules often have a settings option which directly links to the upstream documentation and you basically write the options from upstream into the settings option.
I look all the time in all kind of sources and skip all the tedious and annoying installation steps and just look at the described configs.
My one big question about nix is how the hell do I find out those options? Like cool, I know I need to set the config to some specific value based on arch wiki, but how do I read the nix package to find out what config "key" to use? I've never been able to work out where these are defined
I look at the Nix definition for the relevant module as you often need to see what it's actually doing in order to understand it (yes, it's one of those ecosystems).
For example, for the `steam` program (not package - the package is a dummy): https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/p... and then look for "lib.mk".
Or https://mynixos.com/ which is hierarchically navigable. I usually search for a package or setting name and browse around.
Most people don't realize that you can read the arch wiki and put the same settings into the nixos options. Where is the point in replicating that all again?