Did anyone ever experiment with zig-zag/turbulator tape/stickers on front wing? Widely used in the wind energy industry for increasing wing effeciency at slow speeds.

My roof racks have similar to reduce vibration noise.

I made up some for one of my quite flat bottomed boards. Ran it down the centreline from nose to the start of the foil box. Seemed to make the board unstick a bit better with no noticeable drag penalty when not foiling.
Definitely worth a try.