Pages and pages of people reporting the same issue, and in response the robotic "we are very sorry, check your graphics drivers and windows updates". Are all adobe support people have difficulties understanding plain English?
WE CHECKED, REINSTALED, REMOVED, DDU'D AND UPDATED. MANY TIMES! I EVEN DID A CLEAN WINDOWS INSTALLATION!
YOUR BROKEN APP IS THE ISSUE!
IT'S NOT DRIVERS, NOR HARDWARE, NOR WINDOWS UPDATES AS EVERY OTHER APPLICATION HAS NO PROBLEMS. EVEN ALL OTHER ADOBE APPS.
AND WE ARE PAYING YOU £60/SEAT A MONTH FOR THIS?! WE MUST BE OUT OF OUR MINDS!
I completely understand your frustration and sorry for the trouble you're facing with color picker in XD. As you mentioned that you already tried most of the suggested steps from the related post then I would like to raise a bug for your issue so that our engineering team can look into your issue. For that I would need to document the bug with few information. Would you mind sharing few more details like-
Screenshot of your about XD info page and color picker window.
What is the OS build you're using?
Do you have any dual monitor set up?
Do you have Any HIDPI monitor?
Have you tried uninstalling the graphic drivers and reinstall it?