Thanks for the responses guys. I think the issue was not enough SSD space. I had about 20 GB free and ended up clearing about ~100, and now the game seems to run fine.
I was able to play English Civil War just fine a few days ago. Today, when I tried launching, it just freezes on the "War without an Enemy" screen indefinitely. Additionally, every other AGEOD game on my system now freezes on its own respective splash screen (CWII, TYW, Espana 1936 are wha...