You need to fix firstly the boat/motor aeration, ventilation issue before venturing blindy swaping other prop. A les prop pitch will ventilate worse as will up the wot rpm more than before.
If pushing a heavy boat prop should not ventilate unles the motor sits way up on transom. Will need to go for a OEM Yam prop for motor to rev at its full wot rpm range factory stated for that motor once the aeration issue has been fixed.
What need to do is : inflate boat well, set trim to 90 deg, distribute deck load evenly, go for a wot spin on flat calm water cond if possible, pull head out middle transom and check at which lower leg height is water flow passing by at speed/plane.
If it's passing around the lower AC plate, there's your prop aeration issue, need to lower the motor for flow to skim right under the upper plate which is the hotspot height for any given motor brand with large plates distance as found in the lower leg area.
This is the ideal lower leg height for top boating, along excellent prop thrust at all water cond, that's from flat calm to choppy/windy ones, not extremely though.