Can using two hoses deliver more water?
I would expect more water to flow unless you have extremely low water pressure. You have a 3/4" line and all the water pressure of either a municipal water system or a water pump. Splitting that into two lines will not likely double the flow rate as there is a pressure drop, but it should increase the total flow rate considerably. I would expect it to almost double, but not quite.

This would be easy to test with an empty bucket. Time how long it takes to fill the bucket with one hose on and then with both.