The a21s simply does not have the screen mode option in display settings. My a8 had it and that was 2018. Why is it not on this phone?! Really affects general viewing because of the lack of depth.
A8 has a much better OLED display which supports screen modes. TFT IPS panels such as the one in a21s do not. there is no way to fix this. only oled devices have this, which would be a30 and above
