Ive been in contact w/ customer support for this issue that ive had for the past 2 months or so. There were several things they told me to do, and all of you have probably done them several times over.
After installing 20.2.1 (from 19.9.2) i got ONE Black screen.
Then.....
What seemed to "work" for me (and by work i mean i haven't had a black screen in over a week), is by adding the following registry tweak. I also force closed MS edge at the time, so im not sure if this had a role aswell.
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Avalon.Graphics\
add DisableHWAcceleration 1 (DWORD)
Doing this allowed me to play for several hours w/ no problems. Mind you i still do get crashes, freezes, but no black screens that force me to reboot. That's at least a step up. 
The funny thing is i removed this tweak to test for a black screen and so far ive still havent had any. Edge is running aswell. IM not sure what the heck this problem is. It sure is a strange one.
Give it a try if you haven't.
