May have a (hopefully temporary) fix for some of you out there;
I didn't read through whole thread past the first page. This just started happening to me after the latest KB Update as of todays date (KB5035845) since KB5034441 fails to install for me. My set up is as follows:
i9-7900X
ASUSTeK PRIME X299-DELUXE (LGA 2066 R4)
EVGA RTX 3080
32 GB DDR4-2666
1 TB Samsung 970 Plus MVNE SSD
2 TB Samsung 870 EVO SATA SSD
ASUS ROG STRIX RGB 1000W Gold
#1 LG 48 inch 4k OLED (48C1AUB)
#2 ViewSonic 32 inch 4k HDR Monitor
After trying most of the things listed here, and them not working, I tried =
Nvidia Control Panel > Display > Set Up G-SYNC(tm)
I selected my second monitor (ViewSonic 32 inch 4k HDR Monitor) and then unchecked "Enable G-SYNC, G-SYNC Compatible"
(This was previously checked "On" with the sub option "Enable for full screen mode" selected beneath it)
Hit Apply
Suddenly my second monitor has stabilized. I'll Update here if there's any change. Hope this helped at least one person.