Yeah that's super helpful for NixOS configuration options. What trips me up more is configuring particular packages. Usually it's where I want to configure a particular version or github commit of a package for some reason (usually I want a bug fix).

However, a bunch of packages are defined in some bespoke way with various custom config inputs that generate other bits of config and generally are hard to understand. Thinking it through, I'm not sure it's possible for the OP's tool to solve this particular problem.