Here is the thing. It goes back further to the neolithic age. The cultures found at Mount Carmel in the Judean mountains spread and split into other tribes, that split into even more other tribes. Just like sects of religions do. And even though they were all from the same origin they have now developed their own unique cultures. Then they naturally start conquering each other for resources even though they had the same parents and grandparents. Just like families do for wealth inheritance when someone passes. They didn’t begin as all separate tribes like we subconsciously assume. The sea people came from the levant in the first place and then returned back to the levant to invade it later.
I like your theory