Custom Editor for GameObject Class look like Unity's Custom Inspector for GameObject?

Hi, I'm trying to make a Unity Custom Editor for the GameObject Class. I'd like it to look just like the Untiy Custom inspector pictured below with an extra button showing beneath it.

So I thought I'd call DrawDefaultInspector because that will draw what it looks like by default using the following code:

 using UnityEngine;
 using UnityEditor;
 
 [CustomEditor(typeof(GameObject))]
 public class InspectorNewScriptButton : Editor 
 {
 
     public override void OnInspectorGUI() 
     {
         DrawDefaultInspector();
         if(GUILayout.Button("Press Me")
             Debug.Log("Pressed");
     }
 }

Instead however... I ended up with this mess:

How would I go about making my custom script look/work like Unity's Custom Default not the real default and then add an additional button to it? Is there a call to Unity's Custom Inspector that I'm not aware of?