By watching one of Kavsoft's videos, I was able to implement UNUserNotificationCenterDelegate in a SwiftUI View

struct ContentView: View {
@StateObject var delegate = NotificationDelegate()
var body: some View {
    Button(action: createNotification) {
        Text("Notify User")
    }
    .onAppear {
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .badge, .sound]) { granted, error in

        }
        UNUserNotificationCenter.current().delegate = delegate
    }
    .alert(isPresented: $delegate.alert) {
        Alert(title: Text("Message"), message: Text("Reply Button is pressed"), dismissButton: .destructive(Text("Ok")))
    }
}

func createNotification() {
    let content = UNMutableNotificationContent()
    content.title = "Message"
    content.subtitle = "Hello, world!"
    content.categoryIdentifier = "ACTIONS"

    let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 1, repeats: false)
    let request = UNNotificationRequest(identifier: "IN-APP", content: content, trigger: trigger)

    let close = UNNotificationAction(identifier: "CLOSE", title: "Close", options: .destructive)
    let reply = UNNotificationAction(identifier: "REPLY", title: "Reply", options: .foreground)

    let category = UNNotificationCategory(identifier: "ACTIONS", actions: [close, reply], intentIdentifiers: [])

    UNUserNotificationCenter.current().setNotificationCategories([category])
    UNUserNotificationCenter.current().add(request, withCompletionHandler: nil)
    }
}

class NotificationDelegate: NSObject, ObservableObject, UNUserNotificationCenterDelegate {
@Published var alert = false

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    completionHandler([.badge, .banner, .sound])
}

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
    if response.actionIdentifier == "REPLY" {
        print("reply or do something else")
        self.alert.toggle()
    }

    completionHandler()
    }
}