Customising TabView styling

The default design of TabView is 90% close to what I want. However, the icons, to my eye, lack a sufficient amount of spacing at the top, and slightly too much white space at the bottom.

Is there a way to give more top padding to the icons? To move the icons down without changing the height of the TabView itself?

Also, I find it weird that .labelStyle(.titleOnly) works on Tabs but .labelStyle(.iconOnly) doesn't work. Is that a bug? I had to use Image instead of Label:

        TabView {
            Tab {
                MailView()
            } label: {
                Image(systemName: "envelope")
                    .padding(20)
            }
            
            Tab {
                SettingsView()
            } label: {
                Image(systemName: "gearshape")
                    .padding(20)
            }
        }