Romance of the Three Kingdoms XI
That's a really fun game. It's pure strategy, though. Don't expect much of the semi-RPG focus of other instalments. There's no wandering officer for hire mode, just being a ruler and commanding armies. There are still the requisite personal battles and 'disputes', and you can marry your officers, iirc, but all that is in service of managing a kingdom and generally just being a warlord.
That said, I love it. Fantastic visual design and heroic battles. Really captures the feel of the period, as imagined in the novel (this game made me attempt to read the books, but I can't say I ever managed to finish the undertaking - at some point it becomes a boring Zhuge Liang wankfest - although I'll always remember Liu Bei eating a guy's wife).
I don't know about the difficulty. Maybe the first few tries, when you still learn how it all works. There's a point when it even becomes trivial to win, and all that's left to enjoy is the feeling of living through some heroic deeds. But there's a period in-between stumbling around and expertise when the game feels challenging and really, really fun.
You should be able to squeeze a few good hours of enjoyment out of this one.