Same issue here, I also posted on the FS site.
I too am having the same issue with a new Samsung 49" ultrawide.
New Samsung 49" ODYSSEY G9 Gaming Monitor LC49G97TSSNXDC (5120x1440) with Latest firmware update
NVIDIA 1080 Ti, with control panel settings under program at recommended values. HDR “on”, 120 Hz refresh rate and Nvidia G-Sync “on”, Nvidia color depth settings at 8 bpc
2020 graphics settings at high end and ultra
I7-4790 @ 4.7ghz
As a note, my earlier 43" 4K Samsung monitor was crystal clear, but the refresh rate was 60hz, really had no problem with the monitor except it all of a sudden it quit working.