How to get all the tree loop levels when recursive ? ?

 using System.Collections;
 using System.Collections.Generic;
 using UnityEditor;
 using UnityEditorInternal;
 using UnityEngine;
 
 public class GetChildsEditorWindow : EditorWindow
 {
     public Transform transform;
     int levelsMin = 0, levelsMax = 1;
     static int currentLevel;
     List<Transform> allChildren = new List<Transform>();
     static int oldLevel = 0;
     Vector2 scrollPos;
     public int levelNum = 0;
     public int totalLevels = 0;
 
     // Add menu named "My Window" to the Window menu
     [MenuItem("Get Childs/Get")]
     static void Init()
     {
         oldLevel = currentLevel;
         // Get existing open window or if none, make a new one:
         GetChildsEditorWindow window = (GetChildsEditorWindow)EditorWindow.GetWindow(typeof(GetChildsEditorWindow), false, "Get Childs");
         window.Show();
     }
 
     private void OnGUI()
     {
         GUILayout.Space(20);
         transform = EditorGUILayout.ObjectField("Transform to get childs", transform, typeof(Transform), true) as Transform;
 
         EditorGUI.BeginDisabledGroup(transform == null);
         currentLevel = (int)EditorGUILayout.Slider("Slider", currentLevel, levelsMin, levelsMax);
         EditorGUI.EndDisabledGroup();
 
         if (allChildren != null && allChildren.Count > 0)
         {
             EditorGUILayout.BeginHorizontal();
             scrollPos =
                 EditorGUILayout.BeginScrollView(scrollPos, GUILayout.Width(400), GUILayout.Height(400));
             for (int i = 0; i < allChildren.Count; i++)
             {
                 allChildren[i] = EditorGUILayout.ObjectField("Transform " + i.ToString(), allChildren[i], typeof(Transform), true) as Transform;
             }
             EditorGUILayout.EndScrollView();
             EditorGUILayout.EndHorizontal();
         }
 
         if (oldLevel != currentLevel)
         {
             if (transform != null)
             {
                 allChildren = new List<Transform>();
                 IterateOverChild(transform, currentLevel, levelsMax);
                 oldLevel = currentLevel;
             }
         }
     }
 
     public void IterateOverChild(Transform original, int currentLevel, int maxLevel)
     {
         if (currentLevel > maxLevel) return;
         for (var i = 0; i < original.childCount; i++)
         {
             Debug.Log($"{original.GetChild(i)}");
             allChildren.Add(original.GetChild(i));
             IterateOverChild(original.GetChild(i), currentLevel + 1, maxLevel);
         }
     }
 }

What i want to do is that the loop will start automatic with a button maybe and will loop deep through all the levels and will give me the the whole number of levels there is and when i move the slider display the level number of each objects what object belong to what level.

I can't figure how to make the automation mapping.