That style of outlining doesn’t need a fancy shader - check out the Stylised Content Example on how to do this. It’s a different method that uses a per-object-shader. You could improve it by adding a Fresnel filter as well.
I guess I should say that you CAN do that effect in the Advance Cel Shader. It can flatten the fill colour and do depth outlining. If you’re not looking to do any post-process shader work yourself, this package will do it for you.