I thought of creating something similar and I was going to use a personal fork of the Go compiler with some mods, anko (which is a really cool go binding language) or righting my own DSL. It's quite the undertaking.

I like Nix and NixOS a lot, its really cool, but it has some really odd management issues and the language IMO is horrendous. I used NixOS for around a year and I was changing my Nixpkgs version and I got that same generic nonsense error that doesn't have any semantic meaning and I was just over it. I'm not too fond of commenting out random parts of code to figure out where something minor and obscure failed. Sometimes it tells you the module it had a problem with, or will point out an out of place comma, and other times its just like "idk bruh ¯\_(ツ)_/¯ "failed at builtin 'seq'" is the best I can do"

the paradigm is a million dollar idea though. I have no doubt its the future of a large portion of the future, both for programming and generic systems. I just wish it wasn't a pain to write and it had some sensible error handling.