Might have accidentally started WW1
So my aggressive expansion hasn't gone unnoticed and just about everyone hates me. I'm on ok terms with France, and allied to Austria and Muscovy, but other than that...
I was pretty confident my alliances would keep the coalitions at bay, however, until Muscovy was fighting the Timurids, Golden Horde, Kazan, and Uzbek all at the same time, while Austria took on the Ottomans. While my allies were occupied, my enemies struck. Everyone in red was in the coalition against me, and declared on me at once. I couldn't call either ally in.
I quickly consolidated naval control by crushing the combined Swedish/Polish fleets (80+ trade ships and 20 heavy warships are nothing to scoff at). I then pulled all of my men out of Germany and into Scandinavia, while recruiting mercenaries as fast as I could. The coalition started with about 200k soldiers (didn't think to get a screen of the army counts, at one point it was 230k to 30k). I quickly upped my armies to 50k through mercenaries and began dispatching Sweden.
Bavaria and her allies occupied about 3/4 of my territory, and wanted more. I let about 60k men cross in to Fyn (the first little island in Denmark) and trapped the idiots there with my navy. That would help to level the playing field a bit, even if it meant conceding another siege.
At this point my war exhaustion was skyrocketing and my income was plummeting (due to the occupied territory). I had gone from making about 50 gold a month to losing more than 100 per month. My manpower was depleted and I needed help. I sent Muscovy a gift of 700 gold allowing them to pay off all their debts they accrued to the East. Austria wrapped up their war against the Ottomans. I called them both in at once.
That instantly changed the tide. Overall, troop levels were about equal (200k a side), but since 60k of the enemy were stranded (and slowly dying due to attrition), we were able to swing the war in my favor. The warscore flipped instantly from a -16 to a +11. I was able to manage the ridiculous amounts of War Exhaustion my occupied provinces were giving me thanks to my god-ruler (4/6/4, so able to produce lots of diplo points for manual WE reduction). Being "Reformed" (calvinist) meant that I could apply a 10% bonus to my troops morale thanks to fervor, so that helped.
By the end of the war, both sides had depleted their armies down to about 100k each, but I had won. All told, I probably spent around 5000 gold winning the war.
This map reflects Europe after the war. And that's how I turned a punitive war into the single-largest landgrab in my game yet.
As a bonus, now Austria and Poland really hate each other, and Poland is much more manageable. I'm teetering on the verge of abandoning Austria in favor of France though. It has to happen at some point if I intend to found Germany. Easiest way to accomplish this will be by attacking Brandenburg, but that would unfortunately also draw Poland back in and I'm not sure that wouldn't be biting off more than I can chew.
Waiting allows me to rebuild my monetary stores as well as my manpower, but it allows Austria to do the same. They are injured now - I can't wait long to strike.