Edit: I took a while to post this and I see you have already tried the tail swap, so I don't know.
My first foils the 200 and 280 Go foils were pretty noisy, my Axis have been pretty good.
A couple have made a little bit of noise at times but a light sand on some rough spots or on the trailing edge using the Donaldson method quietened them, most are near silent.
It is usually the tail wing causing the noise, try sanding that especially the trailing edge.
As per the Donaldson method it will be the opposite side to the front wing that you want to put the angle on.
From memory it is the underside of the front wings but the top side of the tail wing.
It sounds like you have already tried that though I 'm just not sure if you tried the tail wing?
Or as DWF says try a tail swap.