ios – Learn how to ignore Dynamic island’s inset/padding

I am looking how this app ignore dynamic island’s default inset, to set a grey background to is’s backside space.
some app
Whereas I check each API AcitivityKit provide, I cant’t extent my view to the inset.
my app

I attempted padding, contentMargins, none of those labored.

ActivityConfiguration(for: ONELiveActivityInfoAttributes.self) { context in
            // Lock display
        } dynamicIsland: { context in
            DynamicIsland {
                DynamicIslandExpandedRegion(.main, precedence: 0) {
                    // some view
                }
                DynamicIslandExpandedRegion(.trailing) {
                    // some view
                }
                DynamicIslandExpandedRegion(.backside, precedence: 1) {
                    VStack {
                        Shade.white
                    }.background(Shade.white).padding(-100).offset(y: 10)
                }.contentMargins(.backside, 3)
                
            } compactLeading: {

            } compactTrailing: {

            } minimal: {

            }
            .contentMargins(.all, 2, for: .expanded)
        }