How to call functions in an editor window at runtime

As the title suggests i need to be able to call a function inside an editor window at Unity runtime (not in build!). However i am currently not able to do so.

I create my window using the following code

 [MenuItem("TestWindow/Add Window")]
     public static void AddWindow()
     {
         TestWindow window = ScriptableObject.CreateInstance<TestWindow>();
         window.Show();
     }

And have the following functions inside TestWindow:

 public class TestWindow : EditorWindow
 {
     private Rect testPanelRect;
 
     private void OnEnable()
     {
         Debug.Log("created");
     }
 
     private void OnGUI()
     {
         DrawTestPanel();
     }
 
     private void DrawTestPanel()
     {
         testPanelRect = new Rect(0, 0, position.width, position.height);
         GUILayout.BeginArea(testPanelRect, EditorStyles.toolbar);
         GUILayout.BeginHorizontal();
         GUILayout.Button("TestButton", EditorStyles.toolbarButton, GUILayout.Width(50));
         GUILayout.Space(2);
 
         GUILayout.EndHorizontal();
         GUILayout.EndArea();
     }
 
     public void DoSomething()
     {
         Debug.Log("I want to be able to call this function at runtime");
     }
 }

However when i try to call DoSomething i get the error NullReferenceException: Object reference not set to an instance of an object. I know what the error means but since it is an editor window it can not be set as an instance of an Object, and i thought that creating an instance of it using ScriptableObject would allow me to call to it in unity runtime. Am I missing something here?