I found Nix just really hard to work with. The documentation was just so poor and every aspect of Nix just seemed to be divorced from pragmatism.
An example of this, years ago, was that I wanted to do something VERY simple: codify the creation of a directory in NixOS. It took me 6 HOURS to find the relevant code for doing that. I couldn't even get an answer out of the Discord server.
I don't know if I'll ever pick it up again. The learning curve was incredibly steep and it's just not on job descriptions and I've never worked in a shop that has used it. I tried it out as a curiosity, found that it was hair pullingly frustrating to use, and moved on.
Just point your agent at a machine0 VM and say "make a machine that does X", then you get code you can use to build on any nix box and you'll always get the same result.
Once you experience this, it's hard to go back to a "traditional" OS, you'll want to nixify everything :)