So, the front camera notch area where you see time and battery isn't being filled up by the game screen. It shows dark there, no display. I think this is an issue with all the OnePlus phones. So, don't ask for system logs and stuffs.
My vivo phone has an option to choose to the apps that can take advantage of full screen display in fun touch OS. Unfortunately, there is no such option for OP's OxygenOS.
Last edited: Sep 29, 2020