Every account is assembled from what survived, by someone who already knows the ending. That single fact makes events look more inevitable than they were — and explains why careful history sounds less certain.
A rising power wants influence matching its strength; an established one sees each concession as erosion. Both are sincere, neither needs to want conflict, and the pressure builds anyway.
The Bronze Age Collapse wasn't caused by one disaster. It was caused by an interconnected system with no slack left to absorb several small ones.