how to change the size of the iPad pointer highlight on a toolbar button

Question

I’ve set up a basic sample project that has a toolbar with an sf symbol button. I would like to change the size of the highlight that is shown when the button is selected with an iPad cursor. I tried changing the frame, which works with a normal button, but not when one is in the toolbar. here is my code:

NavigationView {
            VStack {
                Text("Hello World!")
            }.toolbar {
                ToolbarItem{
                    Button(action: {}) {
                        Image(systemName: "square.and.arrow.up")
                    }
                        .frame(width: 20, height: 20)
                        .padding(0)
                }
            }
        }