How to hide `TabViewBottomAccessory` when drilling down?

I would like to conditionally render TabViewBottomAccessory because I don't want to show it when I am drilling down. When going to the child view I want to hide both tab view (which I achieved by .toolbarVisibility(.hidden, for: .tabBar)) and its accessory.

1. @Environment(\.tabViewBottomAccessoryPlacement) doesn't have a setter
2. another .tabViewBottomAccessory down the tree has no effect
3. my custom @Environment(\.isTabViewBottomAccessoryShown) has no effect on it

#Preview("PreviewView") {
    PreviewView()
}

enum Destination {
    case child
}

struct PreviewView: View {

    @State var tab: Int = 0

    var body: some View {
        TabView(selection: $tab) {
            Tab(value: 0) {
                NavigationStack {
                    List {
                        NavigationLink("To Child", value: Destination.child)
                    }
                    .navigationDestination(for: Destination.self) {
                        switch $0 {
                        case .child:
                            ChildView()
                                // 1 
                                .environment(\.isTabViewBottomAccessoryShown, false)
                                .toolbarVisibility(.hidden, for: .tabBar)
                                // 2
                                .tabViewBottomAccessory {
                                    EmptyView()
                                }
                        }
                    }
                }
            } label: {
                Label("Tab 1", systemImage: "checkmark")
            }
        }
        .tabViewBottomAccessory {
            TabViewBottomAccessory()
        }
    }
}

struct TabViewBottomAccessory: View {

    @Environment(\.tabViewBottomAccessoryPlacement) var placement
    // 3
    @Environment(\.isTabViewBottomAccessoryShown) var isTabViewBottomAccessoryShown

    var body: some View {
        Text("'\(placement)' '\(isTabViewBottomAccessoryShown)'")
    }
}

struct ChildView: View {

    var body: some View {
        List {
            Text("Child")
        }
    }
}


//

public struct TabViewBottomAccessoryVisibilityKey: EnvironmentKey {
    public static let defaultValue: Bool = true
}

extension EnvironmentValues {
    public var isTabViewBottomAccessoryShown: Bool {
        get { self[TabViewBottomAccessoryVisibilityKey.self] }
        set { self[TabViewBottomAccessoryVisibilityKey.self] = newValue }
    }
}

Environment values don't work because the tab bar bottom accessory is not a descendent of the navigation destination. Environment values are only propagated down the hierarchy.

The tab bar bottom accessory is actually a cousin of the navigation destination - they share a common ancestor (the tab view) but one is not a parent of another. I would use a PreferenceKey to propagate the "preference" of whether they want the accessory view to be hidden, to PreviewView.

struct ShouldHideBottomAccessory: PreferenceKey {
    static let defaultValue = false
    
    static func reduce(value: inout Bool, nextValue: () -> Bool) {
        value = value || nextValue()
    }
}

enum Destination {
    case child
}

struct PreviewView: View {

    @State private var tab: Int = 0
    @State private var shouldHide = false

    var body: some View {
        TabView(selection: $tab) {
            Tab(value: 0) {
                NavigationStack {
                    List {
                        NavigationLink("To Child", value: Destination.child)
                    }
                    .navigationDestination(for: Destination.self) {
                        switch $0 {
                        case .child:
                            ChildView()
                        }
                    }
                }
            } label: {
                Label("Tab 1", systemImage: "checkmark")
            }
        }
        .onPreferenceChange(ShouldHideBottomAccessory.self) {
            shouldHide = $0
        }
        .tabViewBottomAccessory {
            if !shouldHide {
                TabViewBottomAccessory()
            }
        }
    }
}

struct ChildView: View {

    var body: some View {
        List {
            Text("Child")
        }
        .preference(key: ShouldHideBottomAccessory.self, value: true)
    }
}


struct TabViewBottomAccessory: View {
    var body: some View {
        Text("Accessory")
    }
}

Note that this doesn't work in beta 2 (the app crashes when you navigate back to the root), but it does work in beta 3.