I've seen several Mac users have the same experience: going all-in on nix-darwin and then getting frustrated. But nix-darwin is one of the worst ways of getting into Nix, because its goal is to make your whole macOS system configurable with Nix, but macOS is a moving target and (unlike Linux) not built to be modular at all. I know people put a lot of hard work into nix-darwin, but it's simply not the main focus of Nix as a whole and sadly it might not ever become a seamless experience. (I'm not a mac user so not keeping up, but I do see colleagues trying it out from time to time.)

The solution here is: use Nix but don't use nix-darwin (at least not until you're generally comfortable with Nix for package management and dev shells). You do NOT have to use nix-darwin on Mac to reap 80% of the benefits of Nix (especially in a team setting).

After dropping nix-darwin, I think almost everyone will find that it's very easy to use Nix for sharing project setups with bespoke tooling. I just had a new team member onboard, knowing nothing about Nix, in a day or less, with several different languages and unusual tools.