Edit: I should say, there are MacOS-unique difficulties if you want to bundle your nice PyQt5 script into a standalone MacOS app bundle using PyInstaller. But that's a separate issue.
It will setup exactly what was asked for. Specifically qt 5.9.5 with PyQt.
>> How well does that work on OSX?
> conda install pyqt
Your comment, while presenting a potential solution to the original problem, did not make sense in context and went off in another direction entirely.
> I’ve tried many times over many years, but never got a satisfactory working Python + Qt development environment working on the Mac.
On Linux you might want to get the distros qt/qt-dev packages, as usual. But as far as I can recall, you generally don't have to.
But all of these things have improved greatly, in my recent experience.