SwiftUI: unwanted split view on iPad

Question

You can apply the .navigationViewStyle(StackNavigationViewStyle()) modifier to the NavigationView!

... 
    NavigationView {
        Text("Hello world!")
    }
    .navigationViewStyle(StackNavigationViewStyle())
...

Edit: Below, I am answering Alexandre's questions from his comment:

• Why full view is not the default for iPad? That's just a choice made by Apple...

• Why this modifier goes outside of NavigationView closure, while the Navigation Title goes inside... Maybe this gives clarification: https://stackoverflow.com/a/57400873/11432719

To use this split style for iPad but remove for iPhone:

    extension View{
    func phoneOnlyStackNavigationView() ->some View{

        if UIDevice.current.userInterfaceIdiom == .phone{
            return AnyView(self.navigationViewStyle(StackNavigationViewStyle()))
        }else{
            return AnyView(self)
        }
    }
}