I see the other long thread about this was locked so I'm posting this since I still have the problem albeit just once in Apex Legends since driver 20.4.2. My display suddenly goes black and I can hear the audio keeps going for 15 seconds or so then that goes away to and after a bit longer the computer restarts itself. The other day I was gaming fine for over two hours with no problems, so it's pretty random.
I've tried turning off all extra feature such as Radeon Anti-Lag, Radeon Enhanced Sync etc.
Bellow is my system info (a bit different since it's a Mac, but it's still mostly Intel based stuff inside, i.e. more or less like a Windows PC from 2010 except for the Xeon type processors):