Remove top padding from List

I've seen similar questions like this one here on Stack Overflow, but none of them have been able to answer my question.

I have created a List, but I want to remove the padding space (marked with a red arrow) above the content in the List. How can I remove it when using a GroupedListStyle?

This is a List within a VStack within a NavigationView that is displayed via fullscreenCover:

var body: some View {
  NavigationView {
    VStack {
      taskEventPicker
      myList
    }
    .navigationBarTitle("Add Task", displayMode: .inline)
  }
}

where taskEventPicker is a segmented Picker (boxed in green):

var taskEventPicker: some View {
  Picker("Mode", selection: $selection) { /* ... */ }
  .pickerStyle(SegmentedPickerStyle())
  .padding()
}

and myList is the form in question (boxed in yellow):

var myList: some View {
  List { /* ... */ }
  .listStyle(GroupedListStyle())
}

What I've Tried

Note: I'm looking for an answer that can apply to the GroupedListStyle. I understand that this issue does not occur with PlainListStyle. This padding issue also occurs with the default listStyle.

Xcode version: 12.5

Solution

Firstly, I would say that GroupedListStyle is working as intended.

On iOS, the grouped list style displays a larger header and footer than the plain style, which visually distances the members of different sections.

You say you have tried this, but it does work for me (Xcode 12.5.1):

    List { ... }    
    .onAppear(perform: {
        UITableView.appearance().contentInset.top = -35
    })

You could also hide the list header, by using a ZStack with the List at the bottom of the stack and the Picker over the top. The Picker does have transparency, so you would also have to add an opaque view to act as background for the Picker.

var body: some View {
    NavigationView {
        ZStack(alignment: .top) {
            List { ... }
            .listStyle(.grouped)
            .padding(.top, 30)
            
            Color.white
                .frame(height: 65)
            
            Picker { ... }
            .pickerStyle(.segmented)
            .padding()
        }
        .navigationBarTitle("Add Task", displayMode: .inline)
    }
}

As far as I can see this just appears the same as PlainListStyle would do, but I assume you have a particular reason for wanting to use GroupedListStyle.