看起来你几乎所有的设置都正确，除了...
在prepare for segue代码中，首先要检查所选的行：

guard let indexPath = tableView.indexPathForSelectedRow else {return}

如果从“Edit”操作调用performSegue，则表格视图将不会有选定的行。
对我来说测试起来有点坚韧，因为我没有所有的数据管理和目标控制器，但这应该可以解决这个问题（如果你在故事板中正确设置了segues）：

override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let editAction = UIContextualAction(style: .normal, title: "Add"){(_,_, completionHandler) in
        
        // instead of passing self as sender
        //self.performSegue(withIdentifier: "editQuiz", sender: self)
        
        // pass the indexPath
        self.performSegue(withIdentifier: "editQuiz", sender: indexPath)
        
        // no need to reload data here
        //tableView.reloadData()
    }
    let deleteAction = UIContextualAction(style: .destructive, title: "Delete"){(_,_, completionHandler) in
        CoreDataManager.shared.deleteSomeQuizData(data: CoreDataManager.shared.quizzes[indexPath.row], indexNumber: indexPath.row)
        self.navigationItem.title = "Title \(indexPath.row)" // "\(CoreDataManager.shared.quizzes.count) quizzes"
        tableView.reloadData()
    }
    return UISwipeActionsConfiguration(actions: [deleteAction, editAction])
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    if segue.identifier == "editQuiz" {
        // do something before segue to AddWordsViewController
        if let indexPath = sender as? IndexPath {
            print("editQuiz with IndexPath: \(indexPath)")
        }
    }
    if segue.identifier == "showQuiz" {
        guard let indexPath = tableView.indexPathForSelectedRow,
              let destination = segue.destination as? QuizViewController
        else {
            // note: this will NOT Stop the segue
            return
        }
        destination.from = Int(CoreDataManager.shared.quizzes[indexPath.row].from)
        destination.to = Int(CoreDataManager.shared.quizzes[indexPath.row].to)
    }
    
}

正如我在评论中提到的：* “为了给予自己最大的控制权，不要在那种情况下使用segues ..."*
为此，从情节提要中删除这些片段。
相反，可以根据需要使用类似下面的代码来示例化“目标”视图控制器：

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    
    // instantiate QuizViewController
    if let vc = self.storyboard?.instantiateViewController(withIdentifier: "QuizViewController") as? QuizViewController {

        vc.from = Int(CoreDataManager.shared.quizzes[indexPath.row].from)
        vc.to = Int(CoreDataManager.shared.quizzes[indexPath.row].to)
        
        self.navigationController?.pushViewController(vc, animated: true)

    }
}
override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let editAction = UIContextualAction(style: .normal, title: "Add"){(_,_, completionHandler) in
        
        // instantiate AddWordsViewController
        if let vc = self.storyboard?.instantiateViewController(withIdentifier: "AddWordsViewController") as? AddWordsViewController {

            // do something before showing AddWordsViewController
            self.navigationController?.pushViewController(vc, animated: true)

        }
        
    }
    let deleteAction = UIContextualAction(style: .destructive, title: "Delete"){(_,_, completionHandler) in
        CoreDataManager.shared.deleteSomeQuizData(data: CoreDataManager.shared.quizzes[indexPath.row], indexNumber: indexPath.row)
        self.navigationItem.title = "Title \(indexPath.row)" // "\(CoreDataManager.shared.quizzes.count) quizzes"
        tableView.reloadData()
    }
    return UISwipeActionsConfiguration(actions: [deleteAction, editAction])
}