Using EditorGUILayout.PropertyField on local attributes of the Editor Scripts

Hi everyone, I am trying to display, on a custom Inspector, an attribute of the EditorScript itself that is going to store the given value and use it after a button gets pressed.

With primitive types, enums and Objects References everything works fine.

With custom classes with a custom PropertyDrawer, I can't figure out a solution. What I achieved is getting and showing with no errors the fields I look for, but I can't edit them. A sample of the code I have written will follow:

Has somebody ever had the need of doing this? Is there a simpler way to do what I'd like to achieve? Thanks to everyone in advance for any answer!