FWIW, I used Gemini to write an Objective-C app for Apple Rhapsody (!) that would enumerate drivers currently loaded by the operating systems (more or less save level of difficulty as the OP, I'd say?), using the PDF manual of NextStep's DriverKit as context.

It... sort of worked well? I had to have a few back-and-forth because it tried to use Objective-C features that did not exist back then (e.g. ARC), but all in all it was a success.

So yeah, niche things are harder, but on the other hand I didn't have to read 300 pages of stuff just to do this...