Most ear protectors act as resonators and amplify the wind noise to deafening levels. It is particularly loud when charging upwind on a foil.
I am having some success wearing a neoprene cap or a surf cap with ear covers under the helmet. The wind noise is less and the comfort is better.
BTW There's some people in QLD who have just brought out a soft ski helmetin the form of a beanie.They're working on a neoprene version for water sports.
antiordinary.co/Another option is soft rugby headgear. I saw a picture of Tom Carroll wearing one. Not sure about the gap at the back.