Use a custom SwiftUI view modifier to adapt different modifiers for different system version

customSwiftUIModifier.swift

public extension View {
    func halfModal<Item, Sheet>(item: Binding<Item?>,
                                preferredHeight: CGFloat = 335,
                                @ViewBuilder sheet: @escaping (Item?) -> Sheet
    ) -> some View where Item : Identifiable, Sheet : View {
        if #available(iOS 16.0, *) {
            return self
                .sheet(item: item, content: { item in
                    sheet(item).presentationDetents([.height(preferredHeight)])
                })
        } else {
            return self
                .background {
                    CustomHalfSheetModel(...)
                }
        }
    }
}