MenuController Script (Unity)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
using TMPro;

public class MenuController : MonoBehaviour
{
    [Header("Volume Setting")]
    [SerializeField] private Slider volumeSlider = null;
    [SerializeField] private float defaultVolume = 1.0f;

    [Header("Gameplay Settings")]
    [SerializeField] private Slider controllerSenSlider = null;
    [SerializeField] private int defaultSen = 4;
    public int mainControllerSen = 4;

    [Header("Toggle Settings")]
    [SerializeField] private Toggle invertYToggle = null;

    [Header("Graphics Settings")]
    [SerializeField] private Slider brightnessSlider = null;
    [SerializeField] private float defaultBrightness = 1;

    private int _qualityLevel;
    private bool _isFullScreen;
    private float _brightnessLevel;

    [Space(10)]
    public TMP_Dropdown qualityDropdown;
    [SerializeField] private Toggle fullscreenToggle;

    [Header("Confirmation")]
    [SerializeField] private GameObject confirmationPrompt = null;

    [Header("Levels to Load")]
    public string _newGameLevel;
    private string levelToLoad;
    [SerializeField] private GameObject noSavedGameDialog = null;

    [Header("Resolution Dropdowns")]
    public TMP_Dropdown resolutionDropdown;
    private Resolution[] resolutions;

    private void Start()
    {
        resolutions = Screen.resolutions;
        resolutionDropdown.ClearOptions();

        List<string> options = new List<string>();

        int currentResolutionIndex = 0;

        for (int i = 0; i < resolutions.Length; i++)
        {
            string option = resolutions[i].width + " x " + resolutions[i].height;
            options.Add(option);

            if(resolutions[i].width == Screen.width && resolutions[i].height == Screen.height)
            {
                currentResolutionIndex = i;
            }
        }
        resolutionDropdown.AddOptions(options);
        resolutionDropdown.value = currentResolutionIndex;
        resolutionDropdown.RefreshShownValue();
    }

    public void SetResolution(int resolutionIndex)
    {
        Resolution resolution = resolutions[resolutionIndex];
        Screen.SetResolution(resolution.width, resolution.height, Screen.fullScreen);
    }

    public void NewGameDialogYes()
    {
        SceneManager.LoadScene(_newGameLevel);
    }

    public void LoadGameDialogYes()
    {
        if (PlayerPrefs.HasKey("SavedLevel"))
        {
            levelToLoad = PlayerPrefs.GetString("SavedLevel");
            SceneManager.LoadScene(levelToLoad);
        }
        else
        {
            noSavedGameDialog.SetActive(true);
        }
    }

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

    public void SetVolume(float volume)
    {
        AudioListener.volume = volume;
    }

    public void VolumeApply()
    {
        PlayerPrefs.SetFloat("masterVolume", AudioListener.volume);
        StartCoroutine(ConfirmationBox());
    }

    public void SetControllerSen(float sensitivity)
    {
        mainControllerSen = Mathf.RoundToInt(sensitivity);
    }

    public void GameplayApply()
    {
        if (invertYToggle.isOn)
        {
            PlayerPrefs.SetInt("masterInvertY", 1);
        }
        else
        {
            PlayerPrefs.SetInt("masterInvertY", 0);
        }

        PlayerPrefs.SetFloat("masterSen", mainControllerSen);
        StartCoroutine(ConfirmationBox());
    }

    public void SetBrightness(float brightness)
    {
        _brightnessLevel = brightness;
    }

    public void setFullScreen(bool isFullscreen)
    {
        _isFullScreen = isFullscreen;
    }

    public void SetQuality(int qualityIndex)
    {
        _qualityLevel = qualityIndex;
    }

    public void GraphicsApply()
    {
        PlayerPrefs.SetFloat("masterBrightness", _brightnessLevel);

        PlayerPrefs.SetInt("masterQuality", _qualityLevel);
        QualitySettings.SetQualityLevel(_qualityLevel);

        PlayerPrefs.SetInt("masterFullscreen", (_isFullScreen ? 1 : 0));
        Screen.fullScreen = _isFullScreen;

        StartCoroutine(ConfirmationBox());
    }

    public void ResetButton()
    {

            brightnessSlider.value = defaultBrightness;
            Debug.Log("Current Brightness: " + defaultBrightness.ToString());

            qualityDropdown.value = 2;
            QualitySettings.SetQualityLevel(1);
            Debug.Log("Current Quality: " + qualityDropdown.value.ToString());

            fullscreenToggle.isOn = false;
            Screen.fullScreen = false;
            Debug.Log("Fullscreen or Windowed?: " + fullscreenToggle.ToString());

            Resolution currentResolution = Screen.currentResolution;
            Screen.SetResolution(currentResolution.width, currentResolution.height, Screen.fullScreen);
            resolutionDropdown.value = resolutions.Length;
            GraphicsApply();
            Debug.Log("Current Resolution: " + currentResolution.ToString());

            AudioListener.volume = defaultVolume;
            volumeSlider.value = defaultVolume;
            VolumeApply();
            Debug.Log("Current Volume: " + volumeSlider.value.ToString());

            controllerSenSlider.value = defaultSen;
            mainControllerSen = defaultSen;
            invertYToggle.isOn = false;
            GameplayApply();
            Debug.Log("Current Sensitivity: " + defaultSen.ToString());
            Debug.Log("Inverted Y-Axis?: " + invertYToggle.ToString());
    }

    public IEnumerator ConfirmationBox()
    {
        confirmationPrompt.SetActive(true);
        yield return new WaitForSeconds(2);
        confirmationPrompt.SetActive(false);
    }
}