I'm having the same problem. I get about 45 minutes to an hour of gameplay then it just dumps me back to the desktop. This isn't the only game I have that does this though. I close as many background apps as I can and nothing is overclocked. All my drivers and my bios are completely up to date. I'm almost positive its a problem within windows itself.
Ryzen 7 3800x
EVGA RTX 2080
32gb ram @3600mhz
Windows 10 Home