Is there a way of somehow putting a QGraphicsTextItem so that the text is always displayed undistorted and in the same size with respect to the user?
Imagine a scene that is zoomed in and out, but has points that are marked with a dot and some text. If the texts is part of the scene it is zoomed with the scene and will be unreadable the most of the time.
You need to set QGraphicsItem::ItemIgnoresTransformations flag for text items. See the documentation:

This flag is useful for keeping text label items horizontal and unscaled, so they will still be readable if the view is transformed.
Qt display text in QGraphicsView undistorted, even in IgnoreAspectRatio views