[ShaderGraph] Help with transforming a World Space Vector3 to a Screen Space Vector2

PROBLEM

https://gfycat.com/oldfashionedvibrantdugong

As you can see in the video, I've gotten fairly close. When the tracked object is a certain distance away from the camera, the screen space circle mask effect is perfect. However, when the tracked object moves too close to the camera or too far away, the circle mask no longer works. The problem is that I can't figure out how to transform the tracked object's world position to screen space coordinates. All help is appreciated! Thanks in advance.

Graph

 // Tracked Object Code
 void Update()
 {
         Shader.SetGlobalVector("_PlayerPosition", Camera.main.WorldToViewportPoint(transform.position));
 }

Zoom out of the scene FOV 60 The rest of the graph (Probably not relevant)