There are two lightweight uniform APIs that lets users write Python code that interfaces with Qt regardless of the actual Python-Qt binding:
They both have similar names, which is confusing, and both currently support PySide2, PyQt5 and the older versions of PySide and PyQt4. Both seem reasonably active, neither supports PythonQt.
I’m not sure how much work it would take to contribute support for PythonQt to either of these packages, but it would be terrific if some volunteer made the effort.