A past Qt webinar was so entitled: The Curse of Choice: An overview of GUI technologies in Qt (https://www.qt.io/event/the-curse-of-choice-an-overview-of-gui-technologies-in-qt/). In its description, you could find a list like this:
QWidgets, QPainter, QGraphicsView, Qt Quick 1, Qt Quick 2, Qt Quick Controls 1 and 2, QWindow, OpenGL, Vulkan, Direct3D.
And that's not all; you could also find the following mentioned too: Qt3D, Qt Canvas 3D, QtQuick Canvas.
All these elements refer somehow to graphics, so it is therefore legitimate to ask what is available in Qt for creating graphical UI, and what should be used when.
As always, the answer is it depends. While the choice is wide, if the focus is on usecases and ...