Systems-oriented games are difficult to design well, because there's a lot of stuff that only works if you and the player have a shared understanding of a given system.
One example of this is Frostpunk, where all the difficulty is caused by you now knowing the optimal setup at first. When I played it, I restarted the first scenario about a dozen times before I got it right. And when I did, the game got easy. So easy that there wasn't much to do anymore.