I've had my Q60 75" since December. When we are using the Xbox or Apple TV through the HDMI, the TV turns itself off after 10 minutes or so while we are watching/playing. When we are watching through the TV apps (Hulu, Netflix, Disney+, etc.) it works just fine and will stay on for hours. It is not set to retail mode or anything like that. Any ideas?
I suggest switching out the HDMI cables that you're currently using to some different ones. Is the TV also plugged into a surge protector or the wall outlet?