I have been meaning to give Nix another try. Last time I did, it was an absolute pain in the ass to do anything that broke one of its assumptions.
I’ve been a nixos user for years, out of curiosity what was it you tried that was a PITA?
The package language has a bizarre syntax/semantic that is unlike pretty much every language I’ve touched. The reliance on directly linking to specific paths in the nix store meant that precompiled binaries that expect a standard path won’t work on Nix. There are tools to adjust those paths, but the package I was attempting to work with (Apache Directory Studio) wasn’t playing nice with them for whatever reason. I finally gave up and made a Flatpak.
I also had problems with it, but after an upgrade it works pretty well.
calamares make nixos install easy