Naval upkeep slider and the usual maintenance goods. Not sure if you also be at high lvl port (do steamers get fixed at lvl1?). Check that you haven't disabled purchasing of convoys and artillery and also if you are able to buy them.
There are three Germanies. NFG, SGF and Germany. First is made of North German culture pops and provinces. Second one is of southeners (BAV and alike, also Austria proper). Both of these are included (needed to form) in Germany. In the most extreme case Germany can include Austria, but none of it's other possessions (HUN etc.). This Greater Germany can be formed by either NGF/Germany or Austria itself (need to release all but Austria as puppets before enabling the decision).
That requires rather much conquering and sphering. Trickiest part is knocking the other major out of GP status so it can be sphered momentarily, but the most annoying part is having to keep an eagle-eye on your sphere as everyone tries to rip it to shreds.
These are good challenges at some point in both HOD and the mod POD. End result is rather too powerful to be interesting, but the journey is worth it.