[__MatrixMan__]

You can use nixpkgs as a single versioned input, and you can also give certain things their own distinct input to be tracked separately in flake.lock, but I wouldn't describe either as a "workaround" for the other.

It is a bit of a headache to have to pick which mode you want for each dependency, but I'm not sure that's a headache that can be dispensed with via UX improvements.

> why even bother using nix instead of mainstream tools with good documentation?

nix lets you have a single source of truth for all of it. It's not nix vs apt or nix vs pip, but rather nix vs (pip & (apt|brew)).

So far as I know, the only other tool that scratches that itch is bazel, otherwise you're kind of stuck with multiple overlapping packaging strategies that don't communicate, which is a recipe for "works on my machine".