SOTA LLMs would probably be fun opponents in turn based 4x.
Unfortunately for it to be sustainable it would need to be an LLM with VRAM usage probably under a couple gigs max so it can run locally on the gaming PC. That said it may well be better than current AI in strategy games.
Will be interesting to find out what they can bring over simply having better SOTA LLM coded opponents (I am sure, we will).