This is how to get the top view controller in swift

TopViewController.swift

var window: UIWindow? {
    guard
        let scene = UIApplication.shared.connectedScenes.first,
        let sceneDelegate = scene.delegate as? UIWindowSceneDelegate,
        let uiWindow = sceneDelegate.window
    else {
        return nil
    }
    return uiWindow
}

func topViewController(controller: UIViewController? = nil) -> UIViewController? {
    let controller = controller ?? window?.rootViewController
    
    if let navigationController = controller as? UINavigationController {
        return topViewController(controller: navigationController.visibleViewController)
    }
    
    if let tabController = controller as? UITabBarController {
        if let selected = tabController.selectedViewController {
            return topViewController(controller: selected)
        }
    }
    
    if let presented = controller?.presentedViewController {
        return topViewController(controller: presented)
    }
    
    return controller
}