The Chaos thing is infuriating and ruining the game for me.
It's bad enough that they do not interact with the rest of the game, at all, in any way. It's as if they're invisible to everyone else, and only exist to hurl doomstacks at you. That's annoying already, but the worst part is that they KEEP SPAWNING ALL THE FUCKING TIME until the final Chaos invasion event is done with.
What does that mean? That means as long as the Warriors and Warherd of Chaos are still alive, you WILL be getting hellmarched by 15-18 doomstacks roughly every 10-15 turns until you manage to hunt down that one single Warherd lord who is hiding in the ass end of nowhere.
Don't rely on the AI to kill of Archaon and friends, because they won't. Meanwhile you'll be dealing with a completely endless pile of bullshit that exists SOLELY to fuck YOU AND ONLY YOU over for no reason other than, I guess, "difficulty".
It's not even that difficult to handle, it's just INCREDIBLY FUCKING TEDIOUS because you absolutely cannot auto-resolve any of these due to how the game fucking hates you for autoresolving Chaos fights. So you spend multiple turns fighting the same fucking battle over and over against Chaos, just to get them the fuck off your shit, and by the time you're done... Archaon and friends aren't dead so HERE COMES SOME MORE FRESH DOOMSTACKS FOR YOU TO TEDIOUSLY GRIND INTO THE DUST AGAIN.
It's fucking irritating and stupid.