I can't beat "Holy Man" campaign on easy :(

I'm super frustrated. I've tried this campaign a dozen different ways and I just can't win. What am I doing wrong / what do I need to do different?

Here's a video of me getting pwned

I converted a Sumerian axmen, walked over to the Akkadian, got another Sumerian axman and a few Akkadian villageers, destroyed Akkadian houses and their town center.

Then I just get fucking destroyed by the Sumerians. Which is basically what happens every time. They get "wheel" very quickly so I can't catch any of their workers, then their horse archers wreak havoc shortly thereafter.