Why does random have the same value?

Question

Unity

I'm making a quiz game where you answer questions, after you've answered the next question, and so on.
I need the questions to be in random order and without repetition, for this I have a variable of type string.
I found one video where everything worked out for a person, but now it randomizes at the beginning, and then I get the same question.
Here is the video

And the code I copied

public Text texxt;

    public List<string> questions = new List<string>();
    public List<int> previousQuestion = new List<int>();

    public int questionNumber = 0;

    public static string selectedAnswer;

    public static int randQuestion = -1;
    void Start()
    {
        texxt = GetComponent<Text>();
    }

    
    void Update()
    {

        if (randQuestion == -1)
        {
            randQuestion = Random.Range(0, questions.Count);

            for(int i = 0; i < 6; i++)
            {
                if (randQuestion != previousQuestion[i])
                {

                }

                else
                {
                    randQuestion = -1;

                }
            }
        }

        if (randQuestion > -1)
        {
           //texxt.text = questions[randQuestion].ToString();
            Debug.Log(questions[randQuestion]);
            previousQuestion[questionNumber] = randQuestion;
            questionNumber++;
        }

   

    }

I already tried to do it myself, but nothing works, there is very little written on the Internet about the random string type in unity

Answer 1

on the Internet, very little is written about the random string type in unity

Because random gives a number. You are not generating a random string, but a random question number.
And why this code should somehow work is not clear at all. What do you think is algorithmically written here?