SwiftUI sidebar list sections should be collapsed by default

Question

I am making an app in SwiftUI with a sidebar that will display hierarchical information. In this case, I am displaying a list of projects and each project will have some to-do lists inside.

My problem as you can see above is that all the sections are expanded by default when the app is launched and I would like that they be collapsed by default instead. I am using List with Section(header:content:) for the sidebar and inside each section is an OutlineGroup.

Here is the code I used

// Data source for the list
class MyEnvironmentObject: ObservableObject {
    @Published var listItems = [
        ListItem(name: "Project 1", children: [
            ListItem(name: "List 1")
        ]),
        ListItem(name: "Project 2", children: [
            ListItem(name: "List 1"),
            ListItem(name: "List 2")
        ]),
        ListItem(name: "Project 3", children: [
            ListItem(name: "Example list")
        ])
    ]
}


struct ContentView: View {

    @EnvironmentObject var dataSource: MyEnvironmentObject
    
    func listItem(for item: ListItem) -> some View {
        Text(item.name)
    }
    
    var body: some View {
        NavigationView {
            List {
                ForEach(dataSource.listItems) { item in
                    Section(header: listItem(for: item)) {
                        OutlineGroup(item.children ?? [], children: \.children) {
                            listItem(for: $0)
                        }
                    }
                }
            }
            .listStyle(SidebarListStyle())
            Text("Hello world")
        }.navigationViewStyle(DoubleColumnNavigationViewStyle())
    }


}

I need a solution ideally using a List with Section, since I believe this is roughly what the built in apps like Files are using for their sidebar (which when opened have sections that are collapsed by default)

I was originally using this solution from SO which involved using DisclosureGroup but I ran into issues formatting on phone/compact display because the List was having dividers by default and I couldn't disable those. I then tried using a LazyVStack instead but it meant I wouldn't get a proper sidebar style especially on Big Sur. This solution is so close but I am not sure how to get the sections to collapse automatically, so help would be much appreciated! ^-^