How to override preference key set in parent with one set in child (mimic navigationBarTitle behavior)

I am trying to use preference keys to mimic navigationBarTitle behavior. In particular I want a child preference key to bubble up and override one set by parent.

In this example I have defined a custom preference key and I set its value twice... right after also setting navigationBarTitle.

Notice that the navigationBarTitle value "Home 2" is overriding the "Home 1" value set in parent. I can't figure out how to also override the parent value of my custom preference key. No mater how I change my reducer function the final value is always the value set in parent, value == 1.

Code Block swift
struct MyPreferenceKey: PreferenceKey {
    static var defaultValue: Int = 0
    static func reduce(value: inout Int, nextValue: () -> Int) {
        value += nextValue()
    }
}
struct MyPreferenceKeyView: View {
    @State var preference: Int = 0
    
    var body: some View {
        VStack {
            Text("\(preference)")
                .navigationBarTitle("Home 2")
                .preference(key: MyPreferenceKey.self, value: 2)
        }
        .navigationBarTitle("Home 1")
        .preference(key: MyPreferenceKey.self, value: 1)
        .onPreferenceChange(MyPreferenceKey.self) { value in
            self.preference = value
        }
    }
}