It is brutal playing the Protestants in 30 years war alright! Youtube has some great crash courses in the history of these wars. The one I watched had a great descrition of the Swedish king, a kid charging into battle at the head of his army in the middle of a blizzard. What a badass! Bet he never got a participation trophy.
Can I recommend to you to check out the famous Polish books by Henryk Sienkiewicz, With Fire and Sword, the Deluge, and Sir Michael, and the films made of the books (Polish but with subtitles)? The Deluge was a story of the last Polish-Swedish war before the one in WOS, about 50 years prior, close enough so that watching the Deluge gets you in the mind of WOS.
Ageod games have really spun me down a deep rabbit hole of history. First with RUS, I had only a broad idea of what the heck was going on, who were these Western Whites and why were they all down in the Ukraine. And why the heck are all the Eastern whites Czecks?! So I commenced the learnings and was all "Ohhh I get it!" I love the story of the Czechs and how they pretty much just "revolted" when the reds tried to take their guns. RUS is more and more becoming one of my all time top games. Now I got TYW, CW2, ROP, WOS...and have just been soaking up historical books and historical fiction!