My MenuHandler Script

using System.Collections;
using UnityEngine;
using UnityEngine.UI;

public class MenuHandler : MonoBehaviour
{

    string difficulty;
    [SerializeField] GameObject difficultyPanel;
    [SerializeField] CustomDropdown dropdown;
    Animator diffPanelAnim;
    [SerializeField] Text currentDifficultyText;
    Button difficultyButton;

    private void Start()
    {
        difficultyButton = difficultyPanel.transform.parent.transform.GetChild(2).GetComponent<Button>();
        //currentDifficultyText = difficultyPanel.transform.GetChild(0).GetChild(2).GetChild(1).GetComponent<Text>();
        diffPanelAnim = difficultyPanel.GetComponent<Animator>();
        ChangeDifficultyText(DifficultyManager.currentDifficulty);
    }

    IEnumerator ChangeDifficultyText(DifficultyManager.Difficulty newDifficulty)
    {
        difficulty = newDifficulty.ToString();
        if (difficulty == "Easy")
        {
            print("changing text to easy");
            currentDifficultyText.text = "Easy";
        }
        else
        {
            print("changing text to normal");
            currentDifficultyText.text = "Normal";
        }
        CloseDifficultyPanel();
        yield return new WaitForSeconds(1.5f);
        difficultyButton.interactable = true;
    }

    public void ChoseEasyDifficulty()
    {
        new DifficultyManager(DifficultyManager.Difficulty.Easy);
        StartCoroutine(ChangeDifficultyText(DifficultyManager.Difficulty.Easy));
    }

    public void ChoseNormalDifficulty()
    {
        new DifficultyManager(DifficultyManager.Difficulty.Normal);
        StartCoroutine(ChangeDifficultyText(DifficultyManager.Difficulty.Normal));
    }

    public void CloseDifficultyPanel()
    {
        diffPanelAnim.SetTrigger("CloseDifWindow");
        Invoke("DeactivateDiffPanel", 0.5f);
    }

    private void DeactivateDiffPanel()
    {
        difficultyPanel.SetActive(false);
    }

    public void OpenDifficultyPanel()
    {
        difficultyPanel.SetActive(true);
        diffPanelAnim.SetTrigger("OpenDifWindow");
    }

    public void ChoseDifficulty()
    {
        switch(dropdown.GetSelectedOption())
        {
            case "EASY":
                print("Chose easy difficulty");
                ChoseEasyDifficulty();
                break;
            case "NORMAL":
                print("Chose normal difficulty");
                ChoseNormalDifficulty();
                break;
        }
    }

    public void QuitGame()
    {
        Application.Quit();
    }
}