That's why we wrote: https://wiki.qt.io/Qt_for_Python#Frequently_Asked_Questions
which highlights:
shiboken2_generator: contains the generator binary that can work with a C++ project and a typesystem to generate Python bindings. Take into account that if you want to generate bindings for a Qt/C++ project, the linking to the Qt shared libraries will be missing, and you will need to do this by hand. We recommend to build PySide2 from scratch to have everything properly linked.