I think "Habsburg" is a good enough descriptor. It encompasses the Catholic, northern-influenced culture (if not actually in the north like Trieste) as well as the baroque, counter Reformation-derived artistic styles.
As someone from Munich, I often joke that if I fell unconscious and woke up in Vienna, it would take me a rather long time to figure out that I’m not in Munich.
I have traveled all over Europe, just about everywhere, and my favorite cities are consistently in the old Habsburg Realm.
I don't know why but that's what they all have in common.