HDR + Gsync + 120hz 1440p = buttery smooth, can't see any obvious raised blacks. black background is still black with white text on it. There is a 'grey' loading screen which initially alarmed me.. but its also present without gsync so i guess the coders just like the colour dark grey. there MAYBE is a subtle gamma change IMO. I think Vincent already touched on this. But its not creating floating blacks.
On the loading screen with gsync there IS a flicker on the bottom left corner. This is also present on my CRG9 monitor which I used to have. I've seen flicker TBH on every single VRR monitor during loading screens + sometimes gameplay. Here there is no flicker during gameplay.
HDR+ 120hz + 1440p + no vsync = buttery smooth, no tearing ( i must be staying within the 60-120hz range quite flawlessly. the colours really don't look very different TBH.
so from my assessment, I will say YES there might be a slight change in black level but NO it is not causing black to become grey which is obviously what we're most worried about.
flicker wise, nothing which affects gameplay. anyone new to VRR, flicker is sadly a thing, and it happens at weird points.. whats important is if it happens during gameplay and it doesn't here. honestly a static loading screen is where I always saw flicker on EVEN the gsync module AW3418DW display
is gsync working? HELL YES. it feels amazing.
and finally .. and surprisingly.. the HDR/120hz/1440p with NO sync is really really quite nice. Obviously not as nice as gsync.. gsync just has something magical there... but its VERY VERY close to the extent only the person holding the mouse can tell the difference IMO... but it could be im lucky im at the sweetspot of framerates.
-> this does make me think, i wonder if panasonic or sony could even just enable 120hz@1440p, it could be awesome for PC users. 1080p is sadly too muddy.
Sorry for the lengthy post.. wanted to give u an honest assessment as best I can with the gear I have in my room.. rather than just write it off as an issue which doesn't exist. I hope my limited experience with other VRR technologies puts into perspective how big or small the issues at with the CX range. I think some people who might be getting anxious about this issue haven't played with many other VRR displays.. or maybe they are lucky and got the perfect ones or didn't notice it. I would say if u didn't tell me there was flicker.. I wouldn't have found it on the loading screen.