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arturpanteleev This might have been said in this thread before, but the reason why Windows 11 22H2 ruined your display is that 22H2 brings Windows ACM (Auto Color Management) to SDR (8-bit) displays.
(For those skimming this thread, this applies to 11 22H2 but not 10 22H2, which remains unchanged.)
This feature has existed since Windows 10 1709 for HDR and 10-bit displays, but this is the first time where it has been rolled out to most PCs.
Starting with version 22H2, Windows 11 offers hardware-accelerated, system-level color management, which means accurate, consistent colors across all Windows apps on every display and less artifacting with gradients, shadows, and darker tones.
This is temporal dithering at the OS level.
The best way to describe ACM is that Microsoft has changed the way Windows fundamentally renders color for the first time in years. Essentially, ACM on Windows implements very similar OS-level color rendering tactics to macOS — AKA, exactly what causes a lot of people here to find macOS unusable.
(As an example, "floating point color" — which is new with ACM on Windows — has been used on macOS since OS X Tiger and has involved temporal dithering since around the era of OS X Snow Leopard.)
Here is an official article from Microsoft about ACM, where they surprisingly say it straight up — Windows now uses 16-bit floating point color ("in-between colors" that are more precise than even a 10-bit display, which means that yes, even 10-bit displays will be dithered), forced color calibration, and dithering on 8-bit displays.
Directly from Microsoft:
When ACM is enabled, the DWM performs its composition using IEEE half-precision floating point (FP16), eliminating any bottlenecks, and allowing the full precision of the display to be used. With ACM, apps can access billions of colors with 10-16 bits of precision, and even on displays that only support 8-bit precision, ACM unlocks additional quality using techniques such as dithering.
Graphics drivers may have caused similar effects in the past, but this is the first time it has become a part of the Windows OS itself on 8-bit displays.
Thankfully, unlike Apple, Microsoft has added a toggle to enable/disable ACM — at least for the time being.
(This might be why @Oshim had a positive experience with 22H2 in contrast to yours, because Microsoft may have listed their device as "ACM incompatible" and disabled it on upgrade instead.)
I don't have Windows 11, but there should be a toggle called "Automatically manage color for apps" within Settings app » System » Display » Advanced display.
Let me know if this toggle is on and if so, turn it off. Hopefully, this will most likely revert 22H2 back to the more comfortable rendering method that 21H2 uses.
If the toggle does not exist, there is a section in the second Microsoft article I linked that mentions a registry key that is also able to control ACM. I sincerely hope that ACM is never made mandatory on Windows.