SwiftUI navigationBarBackButtonHidden not working as expected

Question

I'm having an issue with the navigationBarBackButtonHidden modifier. It doesn't hide the navigation back button...

Here's the source code for the list:

import SwiftUI

struct ContentView: View {
    @State var showSheet = false

    var body: some View {
        NavigationView {
            List(chatsData, id: \.self.id) { chat in
                NavigationLink(destination: ChatView(chat: chat)) {
                    ChatRow(chat: chat)
                }
            }
            .navigationBarTitle("Chats")
        }
    }
}

Here's a preview:

Here's the code for the view I wish to hide the "default" back button:

import SwiftUI

struct ChatView: View {
    var chat: Chat
    @Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
    @State var name: String = "Some text"

    fileprivate var backButton: some View {
        Button(action: {
            self.presentationMode.wrappedValue.dismiss()
        }, label: {
            Image(systemName: "chevron.left")
        })
    }

    var body: some View {
        NavigationView {
            VStack(alignment: .leading, spacing: 0) {
                Spacer()

                TextField("Name's placeholder", text: $name)
                    .clipShape(Rectangle())
                    .overlay(Rectangle().stroke(Color("lightgray"), lineWidth: 2))
                    .lineLimit(5)
            }
            .navigationBarBackButtonHidden(true)
            .navigationBarItems(leading: backButton)
            .navigationBarTitle("\(chat.id)", displayMode: .inline)
        }
    }
}

However, when clicking on a list item from the 1st screenshot, here's what I get:

The "< Chats" back button is still there.

I've managed to hide it by updating the code of the List to:

NavigationLink(destination: ChatView(chat: chat).navigationBarBackButtonHidden(true)) {
    ChatRow(chat: chat)
}

However there's still a huge gap between the top and the title of the next view:

Answer 1

There should be only one NavigationView on one navigation stack, so

struct ChatView: View {
    ...
    var body: some View {
        NavigationView { // << NavigationView not needed here !!!

remove marked navigation view and should work.

Tested with Xcode 11.2, iOS 13.2