无法在 TabBarController 的“更多”选项卡中推送视图控制器

问：

我已经设置了 6 个视图控制器（位于 TabBar 的“更多”选项卡中）：serviceVCfacebookVC

@available(iOS 13.0, *)
private func setupTabs(){
    let home = self.createNav(with: "home", and: UIImage(systemName: "house"), vc: HomeVC())
    let unit = self.createNav(with: "unit", and: UIImage(systemName: "mappin.and.ellipse"), vc: UnitVC())  
    let donate = self.createNav(with: "donate", and: UIImage(systemName: "heart.circle"), vc: DonateVC())
    let infopage = self.createNav(with: "About us", and: UIImage(systemName: "newspaper"), vc: InfoVC())
    let facebookpage = self.createNav(with: "Facebook", and: UIImage(named: "facebookIcon.png"), vc: FacebookVC())
    let service = self.createNav(with: "service", and: UIImage(systemName: "info.circle"), vc: ServiceVC())
    self.setViewControllers([home,infopage,unit,donate,service,facebookpage], animated: true)
}

然后在函数中，它调用以下函数（我可以成功调用它，因为所有 6 个视图控制器中都打印了“pressed”）：createNavhandleButtonTap

@available(iOS 13.0, *)
private func createNav(with title: String, and image: UIImage?, vc: UIViewController) -> UINavigationController{
    let nav = UINavigationController(rootViewController: vc)
    
    
    nav.tabBarItem.title = title
    nav.tabBarItem.image = image
    
    nav.viewControllers.first?.navigationItem.title = ""
    
    nav.viewControllers.first?.navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "list.bullet"), style: .plain, target: self, action: #selector(handleButtonTap))
    return nav
}

@available(iOS 13.0, *)
@objc private func handleButtonTap(){
    print("pressed")
    guard let selectedNavController = self.selectedViewController as? UINavigationController else{return}
    
    let vc = MenuViewController()
    selectedNavController.pushViewController(vc, animated: true)
}

但是，在 和 中，它无法推送 .有什么想法吗？serviceVCfacebookVCMenuViewController()

我绑住了将 和 移动到前面 （ ），然后无法推送新的视图控制器。我猜问题发生在 TabBar 的“更多”选项卡中？serviceVCfacebookVCself.setViewControllers([service,facebookpage,home,infopage,unit,donate], animated: true)unitVCdonateVC