I'm writing this after reading nearly 50 threads this morning of people describing a similar problem.
I have a brand new computer, less than one month old:
ASUS ROG STRIX b450-I (latest BIOS 3004)
Sapphire Radeon 5500 XT Nitro+ 8GB Special Edition
Yesterday when I tried waking my computer from sleep it didn't boot - the spinning logo froze, rebooted twice and made it to the recovery. It boots only in Safe mode.
I have attempted every single suggestion: from DDU to completely nuking and installing a fresh Windows 10 using 5 different ISO images I had (from build 2004 to much older builds).
I reset my BIOS settings to stock, even disabled WiFi, so my installations were completely offline. Tried installing the latest chipset drivers (both from AMD and ASUS websites). Nothing: the driver either fails to install (a black screen followed by an infinite boot loop), or, when installed manually by selecting the .inf - it doesn't boot at all (and even then fails to install, I get a glimpse of a popup saying "reboot required" before it dies).
Tried several of the available Adrenalin drivers, going back few releases.
Finally, I tried it in Ubuntu - it didn't even boot into the OS after the initial setup.
Seeing how this is a problem that affects many people my question is: is the card dead? It's a month old, I'm going to RMA it either way.
Is there really nothing else to be done to diagnose it?