This has a very simple solution. Follow the following steps 1) Go to settings 2) Go to Display 3) Go to App scaling 4) Look for Dead effect 2, then turn the toggle next to it on.
The phone will force full screen on the game then. Any games that don't run on full screen by default can be forced to run full screen with this method
This has to do with how the developer made the games screen scaling which is not compatible with our screen. One solution to get rid of the navigation bar is to change it to Swipe up on Home button navigation You find it in system > Display > Navigation bar > Navigation Bar types
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1) Go to settings
2) Go to Display
3) Go to App scaling
4) Look for Dead effect 2, then turn the toggle next to it on.
The phone will force full screen on the game then. Any games that don't run on full screen by default can be forced to run full screen with this method
You find it in system > Display > Navigation bar > Navigation Bar types