In stereo mode, I noticed a small amount of white noise, consistent with my experiences with the Flight and CloudX Flight. I don’t hold a minor level of noise against any wireless, self-powered product, as they usually have some hiss if you go looking for it.
In surround mode, there’s sometimes a “digital halo/compression” effect around isolated sounds, like the PS4 menu beeps. But I think that’s the result of the EQ profile applied in surround mode and its resulting treble bump, and I didn’t really notice it when continuous audio was playing.
I didn’t think either of these significantly impacted the product compared to other wireless gaming headsets I’ve used, and I stand by my thoughts on their sound in my review. It sounds like you’re having a much worse time, and it might be worth investigating with support. My pair auto-downloaded a firmware update immediately upon installing the new version of Ngenuity from the Windows 10 store. Have you installed that update?
Outside of that suggestion there’s not much more I can say. I reviewed the Corsair Virtuoso alongside these, and the level of white noise/noticeable digital compression was similar. I think the stereo mode on both pairs sounds cleaner. I’m not a high volume listener and didn’t use either at max volume, though the Virtuoso’s amp does have a bit more headroom, so I could see a situation where many users will crank the Cloud Flight S up a little more and notice increased white noise.