Welcome to AoE4 
You can also go here The AI is terrible - #215 by Nacoid24799
Here I have also collected all the AI bugs I have found over time.
Also in my thread people post their bug reportsi about AI . But be sure to post here IV - Report a Bug so that it can be fixed as soon as possible.
And if you want to play against a normal AI, here is a thread with a mod that improves it Jakcie A.I (Actual AI improvements) - #126 by VisionedTuba52.