NavigationControllerSwiftUI.swift

// NavigationControllerSwiftUI.swift 
//  Created by Kanishka on 17/11/21.
// More: https://bio.link/kanishka

import SwiftUI
import UIKit

// Reference: https://stackoverflow.com/a/67495147/7992741

struct NavigationController {
    
    
    /// Pops the current view to the root view
  static func popToRootView() {
    findNavigationController(viewController: UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController)?
      .popToRootViewController(animated: true)
  }
    
    /// Pushes a view controller on top of the current view
    static func pushController(_ controller: UIViewController){
        findNavigationController(viewController: UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController)!.pushViewController(controller, animated: true)
    }
    
    /// Allows a function to do actions with the current navigation controller
    static func navigationAction(_ action: ((UINavigationController)->())) {
        action(findNavigationController(viewController: UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController)!)
        
    }

    
    /// Goes through the application window to find the navigation controller
  static private func findNavigationController(viewController: UIViewController?) -> UINavigationController? {
    guard let viewController = viewController else {
      return nil
    }

    if let navigationController = viewController as? UINavigationController {
      return navigationController
    }

    for childViewController in viewController.children {
      return findNavigationController(viewController: childViewController)
    }

    return nil
  }
}

extension UIApplication {
    
    var keyWindow: UIWindow? {
        return UIApplication.shared.connectedScenes
            .filter { $0.activationState == .foregroundActive }
            .first(where: { $0 is UIWindowScene })
            .flatMap({ $0 as? UIWindowScene })?.windows
            .first(where: \.isKeyWindow)
    }
    
}

struct FirstView: View {
    var body: some View {
        NavigationView {
            NavigationLink(destination: SecondView()){
                Text("Go to another view")
            }
        }
    }
}

struct SecondView : View {
    var body: some View {
        Button("Go to root view") {
                        // popping to root without EnvironmentObject
            NavigationController.navigationAction { navigationController in
                navigationController.popToRootViewController(animated: true)
            }
        }.onAppear {
        // triggering a push or pop to root based on a timer or urlsession completion or async task
            Timer.scheduledTimer(withTimeInterval: 3, repeats: false) { _ in
                NavigationController.navigationAction { controller in
                    var view = Color.red
                    var viewController = UIHostingController(rootView: view)
                    controller.pushViewController(viewController, animated: true)
                }
            }
        }
        
    }
}

Thanks! Do you think we can use this without NavigationView? and have a UINavigationController as the main controller that handles the FirstView?

Yep, it works with that too