the wind at cruise speed is too high in the mix.
Maybe "too high" is the wrong term, but it seems like the level of the sound (even when you turn it down) ends up running the aircraft's sound into a hard limit compressor. I don't even know if MSFS has "compressor" logic in the sound pipeline, but when the cruise wind increases, that sound doesn't just get LOUDER-- it actively turns DOWN the level of "competing" sounds.