I had/have the same Problems like many other owners of the RX 5700 XT. Driver Crashes, Blackscreens etc.
I really tried a lot to find a solution.
I think my System got more stable when i went back to an older BIOS version ( Asus X470 F Gaming: 5007 back to 4804), after clean Installation of Windows not upgrading to Win 10 1903 and the newest Driver 19.7.3.
Now I didn't see a blackscreen anymore but I get a Bluescreen instead.
It says: Video Scheduler Internal Error. Most of the time the System is stable even in Benachmarks like Heaven or Superposition. The BSOD often Comes in Idle mode.
Every time I installed the Drivers I used DDU in safemode before.
I cant really tell if the Card is just broken and a new one would just work fine or if it is a Driver Problem and i just have to wait for more dirver updates.
Maybe some one here has a solution for this Bluescreen or some tipps i did not tried yet.
Asus X470 F Gaming (bios 4048, newest AMD Chipsetdrivers)
Ryzen 5 3600X
32 GB G.Skill Trident Z
RX 5700 XT
Cooler Master V550 PSU
PS.: When i put in my Asus ROG STRIX Vega 56 i have now Problems at all.