I know I sound like a certain member who enjoys matching dynasties and countries, but hear me out. In Christopher Clark's book Iron Kingdom (The Rise and Downfall of Prussia 1600-1947), he says that during the Austro-Turkish War of 1787, Prussia was concerned that the Austrians would make significant gains in the Balkans which would upset the balance of power in the Holy Roman Empire. In 1789 revolts broke out in Austria because of the unpopular war. Apparently Frederick William II encouraged this, and there was talk of trying to re-establish an independent Hungary with a Prussian on the throne.
Is that at all feasible? I suspect that it would require a war against Austria by Prussia. That seems very improbable because of the existing Austro-Russian alliance. Without Russian intervention I suspect Prussia could win such a war with the Austrian army far south being ravaged by disease.
So just for a moment let's say Russia does not intervene and Prussia wins the war, establishing a kingdom of Hungary under a relative of Frederick William II. Presumably concurrent revolts in Lombardia and the Austrian Netherlands have also been successful. I believe Prussia was sympathetic to liberals in Liege at the time, so perhaps a republic would have formed. Bohemia may or may not be gone.
How will this new Hungary fair? Nobles and peasants both will have to be answered to by the new king. The Habsburgs will have been thoroughly humiliated and German dualism greatly changed, not to mention the definite effects on the French Revolution.