SwiftUI TabView not responding

Question

:-) Here comes a probably silly problem with a bit of a preamble sorry!

Long story short - I've been developing an app pulling my hair out due to a bug with the TabView in SwiftUI. I was overlaying the tabs with a ZLayer to add a funky big button in the middle - so when I was running into problems I thought this would be the issue... but this becomes irrelevant in a moment.

For simplicity I started a New project in XCode v11.6, build target iOS 13.6, Selected Tabbed App, created a very simple boilerplate SwiftUI content view with 2 tabs. (For clarity - I did not modify the default code at all). Runs perfectly on the simulator. Plug in my iPhone XS running iOS 13.6.1 (when I first encountered this problem I was on 13.5 so have updated iOS builds whilst this problem has occurred). Run the simple, non modified app on my phone. Loads up "First View", I tap the "Second" tab, nothing. No response at all. This is the same problem I am having in my more complicated app. Occasionally if I keep rebuilding. It will let me switch to "Second View" but then cannot switch back. The Tab Controller just seems to become non-responsive.

Now back to my more complicated app, on the first view there is a scroll view and there is a button with an attached actionSheet. If I pop open the action sheet, then dismiss it (regardless of just calling the .cancel() button or selecting an action), the Tab Controller works perfectly. There is another option which opens another sheet, again as soon as something has been overlayed, everything works as expected until the next app launch.

Tried resetting my MacBook, tried resetting my iPhone, tried uninstalling the build then rebuilding, cleaning the build folder, tried creating multiple projects with build targets iOS 13, 13.2, 13.5, 13.6. Problem seems to persist, but every time the simulator works perfectly.

So my questions here are: From my searching I can't find anyone with this problem. Is it just me really? Can anyone with XCode 11.6 and an iPhone XS please simply hit "New Project" -> "Tabbed App" and let me know if this works? (I'm almost wondering if there's a bug in XCode 11.6 when you create an app and everyone is either working on projects that were already created pre XCode 11.6 or already using the beta XCode... But really I am just out of ideas) Also is there any deeper debugging one can do? Something like actually notifying me for every touch it receives and whether the App sandbox is getting the touch or the OS is (for some reason) keeping the tap gesture? I've never experienced something like this so I can't really see where to start debugging as I don't even know if the app is receiving the tap. Or frankly - does anyone have any other ideas?

Just for clarity - ContentView looks like this: (Again it's straight from what XCode creates for a Tabbed App)

import SwiftUI

struct ContentView: View {
    @State private var selection = 0
 
    var body: some View {
        TabView(selection: $selection){
            Text("First View")
                .font(.title)
                .tabItem {
                    VStack {
                        Image("first")
                        Text("First")
                    }
                }
                .tag(0)
            Text("Second View")
                .font(.title)
                .tabItem {
                    VStack {
                        Image("second")
                        Text("Second")
                    }
                }
                .tag(1)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Thanks in advance and sorry for the long ramble - from a very sleepy dev at wits' end!