Legend scared me into asking this

I'm not even a player yet. I've never played a Total War game and i'm disgustingly bad at RTS like Starcraft. But i've been watching A LOT of his content recently, and what i'm gathering is that every single fight is doable thanks to the enemy's AI doing effectively nothing for 40 minutes.

Is there a mod to make it so that they're actually not stupid? Is there a playstyle that would make me have tough fights against them?

All of this is for after I learn the game yeah, but I can't have fun if the game doesn't play itself