How to Render Unity UI Canvas in between two 3D Objects?

I have a world space UI canvas which I want to render on top of some background 3D objects. So far I have achieved it by setting Order in Layer property of canvas to 1. Now the canvas is rendered on top of 3D Objects in background. For fading effect I am using a shader (Unlit Transparent Color) on shpere which is provided by Oculus as:

 Shader "Oculus/Unlit Transparent Color" 
 {
     Properties 
     {
         _Color ("Main Color", Color) = (1,1,1,1)
     }
 
     SubShader 
     {
         Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
         LOD 100
         Fog {Mode Off}
         Cull Off
         ZWrite Off
         Blend SrcAlpha OneMinusSrcAlpha
         Color [_Color]
 
         Pass {}
     }
 }

Fader is working fine with everything except the canvas which has Order in Layer = 1. Due to this setting UI always appear on top of everything no matter how close I place the fader sphere to the camera.

Is there any kind of settings which can be used to control rendering of 3D Objects on top of a canvas. Like we have Order in Layer for Sprite Renderer and UI Canvas?