there are of course also Windows versions of Qt and its official Python bindings, just look into your link.
The problem is that
pip to be installed in its recommended way like most of Python's 3rd party libraries these days. Cinema's Python does not have the
pip tool and package included. This in turn will make it quite hard, if not impossible, to install
c4dpy, because you would have to handle all the dependencies and setup procedures that are embedded within the
pyside2 wheel (the installation file).
If I was hellbent on using an external GUI, I would probably look into
tkinter, Python's default GUI.
tkinter however, has also been removed from
c4dpy. So you would have to (manually) reinstall this one too, but you would probably have a better time trying to, because
tkinter has no external dependencies except the binaries it comes with, i.e. is less complex than
I think Maxon said at some point, that they did remove
tkinter, because they wanted to disencourage the usage of GUI frameworks other than their own. You can make of that statement what you want, but I want to stress, that there is no guarantee that it is technically possible to get
tkinter running on
c4dpy. Or in other words: It might not only have been a strategic decision to remove that package, but also a technical one.