Currently there is the QGLWindow that holds a QGraphicsScene, where all of our windows are QWidgets wrapped by QGraphicsProxyWidget to get them into the scene.

Are you suggesting that we should do another layer of wrapping the QWebEngineView in a QOpenGLWindow wrapped in a QWidget that is then wrapped in a QGraphicsProxyWidget?

I don't understand why that would help, but I guess you never know.