SwiftUI iPad app opening full screen (as expected) on preview, but in simulator opens minimised in the sidebar

Expected behaviour (and it works this way in the preview): https://i.stack.imgur.com/wLuQY.png

Actual behaviour (in the simulator):
https://i.stack.imgur.com/ZKaAR.jpg

Unfortunately, I do not have a physical device to test it out on at this time.

I've updated the code below to include the 'magic' as maybe I've screwed something up in there. The LoginView and RegisterView are similar (vstack in a zstack) but with text/secure fields for username/password.

import SwiftUI


import SwiftUI


struct ContentView: View {
    
    var body: some View {
        NavigationStack {
            ZStack{
                Color(K.BrandContent.onyx)
                    .ignoresSafeArea()
                VStack(spacing: 0.0) {
                    Spacer()
                    Image(K.BrandContent.logo)
                        .resizable()
                        .aspectRatio(contentMode: .fit)
                        .frame(width: 1000, alignment: .center)
                        .imageScale(.large)
                        .foregroundColor(.accentColor)
                    Text(K.BrandContent.name)
                        .font(.system(size: 70))
                        .fontWeight(.bold)
                        .foregroundColor(Color(K.BrandContent.red))
                    Spacer()
                    NavigationLink(destination: LoginView()) {
                        Text("Login")
                            .font(.system(size: 30, weight: .bold))
                            .foregroundColor(.black)
                    }
                    .frame(width: 300, height: 50)
                    .background(Color(K.BrandContent.white))
                    .padding(.vertical)
                    .containerShape(RoundedRectangle(cornerRadius: 25))
                    
                    NavigationLink(destination: RegisterView()) {
                        Text("Register")
                            .font(.system(size: 30, weight: .bold))
                            .foregroundColor(.black)
                    }
                    .frame(width: 300, height: 50)
                    .background(Color(K.BrandContent.white))
                    .padding(.vertical)
                    .containerShape(RoundedRectangle(cornerRadius: 25))
                    
                }
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
        //.previewDevice(PreviewDevice(rawValue: K.Devices.ipad))
    }
}


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
            .previewDevice(PreviewDevice(rawValue: K.Devices.ipad))
    }
}

The Double Column setup only happens with

NavigationView

Or

NavigationSplitView

If your intended navigation setup is stack.

You should remove all other setups and leave only a single NavigationStack at the very top of the app.