Like everyone else I have similar problems and came across this thread as probably the most useful and informative among the searches I made.
However my problem only occurs on battery power! (Fujitsu S935 laptop with a 5th gen I5). It actually first appeared when I went from Windows 7 to Windows 10 and I eventually cured it by going to the Intel HD Graphics Control panel and modifying the Power settings for the Intel graphics.
In the 20H2 "update" the problem reappeared but although the Intel HD Graphics Control panel starts it then aborts so I can't run it to check the settings. Downloading the newer Intel Control Panel doesn't help as a) it is very unclear whether it applies to slightly older processors, and b) the Power option isn't there anyway. I've tried changing the Advanced settings in the Windows Power options but to no effect.
Anyway, the upshot is that having tried 20H2 twice I have gone back to 1909 again. I will keep searching but have no answer so far.
It seems to me that Microsoft can't stop changing Windows 10 and each time it gets worse rather than better. Perhaps they should just freeze it and stop adding features and just provide bug fixes. It is like building a house and adding extensions for the next 10 years. What you end up with is an unworkable mess.