I do have a crazy, and possibly ASB idea, in which the HRE was just restored in the Congress of Vienna (although, it has the borders of German Confederation, and changes to elections, allowing Protestant royals a chance, so it’s just the German Confederation all in but Name and Titles). So when the Revolutions of 1848, the Habsburg Emperor abdicates the title of Holy Roman Emperor, the remaining Prince-Electors decides on electing some other house to the throne, either a Wittlesbach or a Hohenzollern, and which slowly over the course of decades, leads to more centralization
Still, it’s an outlandish, ASB idea