Just started playing Unity of Command 2, and it took me a good couple of hours and half a dozen attempts just to get through the tutorial. It's very punishing with not much room for error - you basically have to have a thorough understanding of how all of the systems work from the very beginning and make multiple very precise moves, because a single mistake can cost you a run.
This is coming fresh off me playing the Operational Art of War 4, in which the tutorial mission involves playing the Korean War as the DPRK. Same story, I tried it multiple times and got completely wrecked every time. There's supposed to be a Chinese intervention to help when you're about to lose, but I guess I was unlucky because I never saw that in any of my attempts.
I don't think this is just a matter of me being terrible at wargames either, because I've played others like Panzer Corps and Flashpoint Campaigns: Red Storm and found the early missions beatable without much trouble and the difficulty curves comfortable.
The target audience seems to be people that really like fiddling with knobs that control the attributes of tanks.