Changing difficulty settings in an Unity Pong game

Question

I get "NullReferenceException: Object not set to an instance of an object" error, while trying to get a value from another script.

//first script

public class Easy : MonoBehaviour
{
    public int difficulty=0;
    // Start is called before the first frame update
    void Start()
    {
        difficulty = 0;
        GetComponent<Button>().onClick.AddListener(diffchange);
    }

    public void diffchange()
    {
        difficulty = 1;
        SceneManager.LoadScene("5Game");
    }
}

//second script

public class AIMovement : MonoBehaviour
{
    public GameObject ball;
    public float speed;
    // Start is called before the first frame update
    void Start()
    {
        if (GetComponent<Easy>().difficulty==1)// here is the problem, trying to get the value from the first script
        {
            speed = 200;
        }
        

    }

    // Update is called once per frame
    void FixedUpdate()
    {
            if (ball.transform.position.y > this.transform.position.y)
            {
                GetComponent<Rigidbody2D>().velocity = new Vector2(0, 1) * speed * Time.deltaTime;

            }
            else
            {
                if (ball.transform.position.y < this.transform.position.y)
                {
                    GetComponent<Rigidbody2D>().velocity = new Vector2(0, -1) * speed * Time.deltaTime;
                }
                
            }
    }
}

I tried to do it in reverse as well. To change the value in the second script from the first, but it didn't work, i think i got the same error.

//first script
GetComponent<AIMovement>().difficulty=1;
//second script
public int difficulty=0;
...
if(difficulty==1)
...