URP ForwardRenderer - How to change RenderObject material properties

Hello everyone!
Below is a screenshot of my ForwardRenderer. I am overriding the material of objects on my "Objective" layer with my "OutlineGlow" material. Ideally, I want that material to pulse, i.e. I want to be able to modify the properties of the material, similary to accessing properties such as _Color on a MeshRenderer's material. Is there any way of doing this?

Also, is this part of the URP documented anywhere? I am having trouble finding any valuable resources that could give me more insight in as to how the ForwardRenderer works.

 

Did you tried animating material itself?