stageControl.cs

using UnityEngine;

public class stageControl : MonoBehaviour
{
    public bool stageComplete;
    public GameObject stageEnemies;
    public GameObject accessNextStageObject;
    public string defaultOrcustom;

    public bool AreAllChildrenInactive(GameObject parentObject)
    {
        // Loop through all the child objects of the parent
        for (int i = 0; i < parentObject.transform.childCount; i++)
        {
            GameObject child = parentObject.transform.GetChild(i).gameObject;

            // If any child is still active, return false
            if (child.activeSelf)
            {
                return false;
            }
        }

        // If none of the children are active, return true
        return true;
    }

    public void setActiveStageAccessObject()
    {
        accessNextStageObject.SetActive(true);
    }
    public void setInactiveStageAccessObject()
    {
        accessNextStageObject.SetActive(false);
    }

    private void Update()
    {
        if (AreAllChildrenInactive(stageEnemies))
        {
            if (defaultOrcustom != null)
            {
                if (defaultOrcustom == "default")
                {
                    setActiveStageAccessObject();
                }
                else if (defaultOrcustom == "reverse")
                {
                    setInactiveStageAccessObject();
                }
                else if (!stageComplete)
                {
                    stageComplete = true;
                }
            }
        }
    }
}