I haven't played any video games outside of Path of Exile in the last few years but I still played a ton of hours of UG: Civil War. It's like an American Napoleonic linebattle game where you build your army and essentially "take a tour" through some historical and not so historical battles. Fun game. I think I have 500 hours into it but I'm a bit of a sperg and can get sucked into this stuff. If it's ever on sale you should grab it. The difficulty can be nice and the game isn't afraid to kick your ass.
If you do play it, there's a mod pack to install that's found on their Steam forum called "J&P Rebalance" or something. Grab that after you're familiar with the game since it makes it more fun.