ExitTrigger.cs

public class ExitTrigger : MonoBehaviour
{
    [SerializeField] private string levelName;

    private void OnTriggerEnter(Collider other)
    {
        if (other.tag == "Player")
        {
            GameEvents.InvokeSceneChange(levelName);
        }
    }
}

GameController.cs

public class GameController : MonoBehaviour
{
    [SerializeField] private SceneController sceneController;

    private void Awake()
    {
        GameEvents.OnSceneChanged += LoadScene;
    }

    private void LoadScene(string levelName)
    {
        Debug.Log(levelName);
        sceneController.LoadScene(levelName);
        // make music change
        // stop player's movement
    }

    private void Start()
    {
        sceneController.LoadScene("Level_1");
    }

    [ProPlayButton]
    private void LoadScene()
    {
        sceneController.LoadScene("Level_1");
    }
}

GameEvents.cs

public static class GameEvents
{
    public static event Action<string> OnSceneChanged;
    
    public static void InvokeSceneChange(string sceneName)
    {
        OnSceneChanged?.Invoke(sceneName);
    }
}

SceneController.cs

public class SceneController : MonoBehaviour
{
    [Header("References")]
    [SerializeField] private GameObject loadingCanvas;
    [SerializeField] private TextMeshProUGUI tipText;
    [SerializeField] private Slider progressBar;

    [Header("Time")]
    [SerializeField] private float minimumLoadingTime = 5.0f;

    [Header("Tips")]
    [SerializeField] private List<string> tips;

    private string _previousLevel = "";

    private void Start()
    {
        loadingCanvas.SetActive(false);
    }

    public void LoadScene(string levelName)
    {
        StartCoroutine(LoadSceneAsync(levelName));
    }

    private IEnumerator LoadSceneAsync(string levelName)
    {
        Scene scene = SceneManager.GetSceneByName(levelName);

        if (scene.IsValid() && scene.isLoaded)
        {
            yield break;
        }

        if (_previousLevel != "")
        {
            SceneManager.UnloadSceneAsync(_previousLevel);
        }

        _previousLevel = levelName;

        loadingCanvas.SetActive(true);
        tipText.text = tips[UnityEngine.Random.Range(0, tips.Count)];

        AsyncOperation operation = SceneManager.LoadSceneAsync(levelName, LoadSceneMode.Additive);
        operation.allowSceneActivation = false;

        float startTime = Time.time;
        
        while (!operation.isDone)
        {
            var _loadingProgress = Mathf.Min((Time.time - startTime) / minimumLoadingTime, Mathf.Clamp01(operation.progress / 0.9f));
            progressBar.value = _loadingProgress;

            if (Time.time - startTime >= minimumLoadingTime && operation.progress >= 0.9f)
            {
                operation.allowSceneActivation = true;
            }

            yield return null;
        }

        loadingCanvas.SetActive(false);
    }
}