My Dell Latitude 5590 i5 8th gen 's screen goes black with everything still working after leaving it on for some time and it turns on only after shutting it down and restartimg it and I have just bought it. Is it a hardware problem or a there is something wrong with my win 10 config?
Then I would check the rest of the sleep settings. Additionally you didn't mention 'how' you are trying to wake it from sleep/hibernate. So what exactly are you doing that isn't working and making you need to power it off? What are you hitting/pushing/clicking/etc.?