I have create a new project with Xcode 12 I have open Xcode and I have click create a new Xcode project -> select Game and pressed next -> add name and press next -> create on the desktop and deselect portrait. in the GameScene.sks click the scene and enter 812 in the W and 375 H press play and I have the screen with black stripes on the right and left
In Xcode 11 i not haveI've never had any problems, thank you in advance