How to update value of runtime non-serializable in a custom inspector using UIElements?

I try to have a non-editable integer field to display a count in a dictionary, which is managing some of my runtime gameObject use count.

Since I'm using UIElements, all IMGUI thing are ignored by Editor, I can't use Editor.OnInspectorGUI to update value int my custom inspector. And also since the value is not from SerializeObject, I cant use bind.

How can I update it in my custom inspector?