This is my 4th XTX with this issue. Only thing left to test is motherboard change. All have the exact same whine.
I really doubt it could be the motherboard. Sounds like might be the GPU design and there is nothing we can do.
In any case, that is not as bad as the one I had (reference) so definitely worth spending a bit extra on the Nitro. Still, is very annoying spending so much money on something and being far from great