Is it possible to rebuild overlay only and not the body?

Hi. I am not sure how to do this case scenario I am having.

Please see sample code

@State private var tileLayers: [GMSURLTileLayer]?   
@State private var isShowingLegend = true
   
var body: some View {
    MapView(
      tileLayers: tileLayers
    )
    .task {
      setupMenuItems()
       
      if load {
        load = false
        processRainWatcher()
      }
    }
    .overlay(
      isShowingLegend ?
        HStack {
          RainWatcherLegendView()
          Spacer()
        }
        .transition(.move(edge: isShowingLegend ? .leading : .trailing))
      : nil,
      alignment: .bottom
    )
}

This is not a working code. But i wish to ask suggestion. because the overlay shows a legend view. If isShowingLegend.toggle() is triggered, it animates sliding in and out of the screen.

Problem mis, everything gets rebuilt. so the tile layer in the MapView() gets re-rendered again.

is there a way not to let this happen, but still let the legend animate sliding in and out?

or perhaps pass a binding variable to the legend view? and do the animation in that view? so that the parent view does not get rebuilt?

thoughts?