Valdemar II
Banned
Note that Brandenburg started its rise by seizing the opportunity of a "zero hour",
and rebuild everything in a more modern (and more Dutch) way.
Disasters can turn out to be opportunities.
Yes Brandenburg was a interesting case, but even without the reforms following the 30YW it's going to be the second or third violin in the Empire. But it will look much more like OTL Bavaria than Prussia. It's not going to be OTL military behemoth.
In all likelyhood Denmark are going to replace Prussia, the reforms pushed through by Christian IV was moving Denmark that way, and without the loss in the Danish phrase of the 30YW, Denmark would be in a much better position to continue the reforms and avoid the disasterous weakening in 1649-1660 which meant a loss of Scania and the new dominance of the Swedish empire. Even as a erman state greater Holstein are going to be strong player even without the Danish possesions.