Im confused, doesnt the enemy army use the exact same AI as your army? why would yours perform worse
Because the AI gets all wonky depending on what units are currently on the battlefield and the balance of power.
I'm playing with an empire army and have been constantly fighting the Khuzait. I will personally normally kill 50-100 horsearchers/cavalry before going down, but when that happens the enemy still has more cav than me.
This forces my army to get into stupid defensive formations such as "infantry form defensive ring" despite it having no functionality, but the enemy AI will not because they have more cavalry.
For some reason my armies want to take the defensive when they have a huge battle advantage and incur heavy losses moving around doing nothing but the enemy will always just F1 + F3 when they have the advantage.
The enemy AI will also use this strategy when their cavalry are outnumbered and its garbage for them as well. Its just shooting fish in a barrel.
And the enemy they will also spam stupid commands and get troops lost for no reason when they should just charge (but because of the way I position and train my armies it makes no difference in the end result).