This applies to the real humankind as well, but rn I'm venting about the game
My 3rd play-through, each time I had to just give up because bugs just pile up. Can't make peace, can't make war, this last time the game told me my civilization had fallen when an AI captured the last city of another AI...
Try deleting your old saves, that might help
Just deleting? My impression is that saving/loading is the biggest problem.
I had a problem where i would het stuck at end turns but i fixed it by deleting my old saves
apparently having the game folder exist pre-release (ie: you participated in any of the opendevs or the beta, and therefore the game folder and settings already existed) has been fucking shit up for people massively