Yeah, disabling the pre-launcher is nice because you get straight into the game, but it's less nice when it launches into fullscreen and the UI scaling isn't set for a reference target. In the future, I recommend either leaving the pre-launcher on (the hard part in user acquisition is over if they make it to that point anyway), or making use of the "Reference Resolution" property on your root canvas element: https://docs.unity3d.com/Packages/com.unity.ugui@1.0/manual/script-CanvasScaler.html