Is it possible for a NavigationLink to perform an action in addition to navigating to another view?

You can use .simultaneousGesture to do that. The NavigationLink will navigate and at the same time perform an action exactly like you want:

NavigationLink(destination: TradeView(trade: trade)) {
                        Text("Trade View Link")
                    }.simultaneousGesture(TapGesture().onEnded{
                    print("Hello world!")
                })

Use NavigationLink(_:destination:tag:selection:) initializer and pass your model's property as a selection parameter. Because it is a two-way binding, you can define didset observer for this property, and call your function there.

struct ContentView: View {
    @EnvironmentObject var navigationModel: NavigationModel

    var body: some View {
        NavigationView {
            List(0 ..< 10, id: \.self) { row in
                NavigationLink(destination: DetailView(id: row),
                               tag: row,
                               selection: self.$navigationModel.linkSelection) {
                    Text("Link \(row)")
                }
            }
        }
    }
}

struct DetailView: View {
    var id: Int;

    var body: some View {
       Text("DetailView\(id)")
    }
}

class NavigationModel: ObservableObject {
    @Published var linkSelection: Int? = nil {
        didSet {
            if let linkSelection = linkSelection {
                // action
                print("selected: \(String(describing: linkSelection))")
            }
        }
    }
}

It this example you need to pass in your model to ContentView as an environment object:

ContentView().environmentObject(NavigationModel())

in the SceneDelegate and SwiftUI Previews.

The model conforms to ObservableObject protocol and the property must have a @Published attribute.

(it works within a List)

You can use NavigationLink(destination:isActive:label:). Use the setter on the binding to know when the link is tapped. I've noticed that the NavigationLink could be tapped outside of the content area, and this approach captures those taps as well.

struct Sidebar: View {
    @State var isTapped = false

    var body: some View {
        NavigationLink(destination: ViewToPresent(),
                       isActive: Binding<Bool>(get: { isTapped },
                                               set: { isTapped = $0; print("Tapped") }),
                       label: { Text("Link") })
    }
}

struct ViewToPresent: View {
    var body: some View {
        print("View Presented")
        return Text("View Presented")
    }
}

The only thing I notice is that setter fires three times, one of which is after it's presented. Here's the output:

Tapped
Tapped
View Presented
Tapped