Have you made any non-trivial use of the Qt bindings for those languages? Qt is a big and complex library, and most bindings are incomplete or poorly documented. As far as I know, PyQt is the only Qt binding is the only one that you can really rely on to work now and in the future.
There is PySide2/Qt for Python which are the official Python bindings for Qt by the Qt Company itself and they are close enough to the C++ API(since they are auto-generated) that it's possible to just use the C++ documentation and translate any C++ code into python nearly 1:1 (except things like QString where you can just use Pythons native types).
Not terribly complex, but not trivial either. Yes, there are missing pieces in non-python ones. But given that basics are handled, it's often pretty easy to add the pieces which you need.
Qml supports ES7 so you only really need to touch C++ if you're not making "casual small GUI apps". If you need to draw custom items or do low level networking then yeah you need to use C++ but even then Qt is much friendlier than using the standard libraries.
Here is a Qt C++ example:
QString str = "/a/b/c/";
auto parts = str.split('/');
