If its doing it only after 5 minutes then I'd recommend booting into the BIOS and sitting there and see if its fine or not while there. If it fine for 1 hour and you use it at the end of 1 hour and its still working in the BIOS well then it would only be a coincidence and is something in Windows that has changed such as a driver or Windows corruption.
If its only in Windows, check Windows update history for changes today or the last day you used it previously. Same with installed apps list and sort that by date. See if anything was installed for the hardware as well as Windows updates. Note those. You can then see if there's an older restore point available and try that or you can manually change to an older driver or uninstall any Windows updates that it allows.
As far as I know, PUBG shouldn't install anything but I do believe Steam can do something. Possibly anti cheat or whatever with PUBG could create an issue. This should show up in installed apps so hence why its good to look there.
WARNING: You can try uninstalling, restore points, drivers etc if you see anything provided you can do it fast enough so it doesn't crash during it as you wouldn't want that. If that happens then you will need to do some work. If its indeed 5 minutes, that's not much time for anything and is a risk.
If the computer is having a problem even while in the BIOS then it has a hardware problem sadly and would either need to be sent in to Asus for repair or trashed.
Alternatively and also I'd recommend is to try to install or boot a clean OS and see how it works with that. I'm not getting into this though.
Another thing is if there's crash dumps available then a relevant one could be uploaded and linked in so someone could look into it for you. It might specify a driver if that's the problem. Otherwise, it might not help much or at all.
Some other things you could try is a clean boot, safe boot, or in-place upgrade.
How you go about it is subjective. Its better to take the least risky ways first and work up to the worst. I didn't put them in any order.
Backup your files if you didn't. If its fine outside of Windows then backup your files outside of Windows. There's various ways. I'm not getting into that.
You're welcome to wait for someone else who might walk you through things and in their own subjective way.