I think it's a trap when you force people to pick *one* top issue. Yes, most people say the economy, but that doesn't mean the Iran war mattered little.
People were also asked how much of a factor the Iran war was in their voting and 74% said it was a crucial or major factor. 90% said the cost of living was a crucial or major factor and those two things aren't separate.
Almost anyone you ask would admit that the war is what's primarily driving gas prices to record highs. Diesel is even worse, and affects everything transported by truck. When voters say their biggest issue is the economy, a big part of that is the war's effect on fuel prices.