I have similar issues with two of the three ROG Swift PG279Q displays I purchased.
Instead of moaning about it and going through exchange/RMA channels. I decided to matters into my own hands and disassemble them into their component parts to investigate the issues then see can they be resolved by myself. I used a suitable philips head screwdriver (for a screw) then a thin metal spudger to unclip the back casing from the thin metal bezel which... Took a little practice ( I was super careful not to scratch the frame) and worked my way around. Was easier than I initially expected.
Turns out, the dust particles were sandwich between the IPS panel itself and the backlight... Be very careful, wear dust free latex gloves if I were you as any amount of oily fingerprints on any transparent surfaces can cause areas of the screen to become less sharp. I also took this opportunity to sort out the uneven light leaks around the display... This isn't actually due to a faulty display, IMO but how much force is applied to the panel mounts, when the panel is assembled.
Unlike everyone else, I chose to leave the display powered, this way I can see what effect my tinkering would have on the IPS. For cleaning I used a bulb air blower not a can of air, mainly because occasionally cans of air can spray liquids and I didn't want to touch those surfaces if possible.
Images are from here..
https://twitter.com/MsNikitaTV/status/1096416140685914113
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