I'm hitting my face with keyboard right now as i'm writing this. Just create a simple Multiplatform project with xcode 12, and create a simple class or struct anywhere in your project in speared file. If you add a property of type  MTLRenderPassDescriptor, no matter if you even use the created class or struct in your swiftUI code, it will prevent your interface to auto rotate when you are testing in real device. Everything is fine in simulator , but in real device, it is not rotating . Why the swiftUI even care about the MTLRenderPassDescriptor ? I'm sure that it is a bug, but how the hell did that happen ?