swiftui nacigationbar space not hidden code example

Example 1: swiftui navigationview ignore top space

NavigationView {
    FileBrowserView(jsonFromCall: URLRetrieve(URLtoFetch: applicationDelegate.apiURL))
        .navigationBarTitle("")
        .navigationBarHidden(true)
}

Example 2: navigationbarhidden not working swiftui

NavigationView {
    ScrollView() {
     ......
    }.  
    .navigationBarTitle("") //this must be empty
    .navigationBarHidden(true)
    .navigationBarBackButtonHidden(true)
}