In case of someone coming here in the future from a web search and wondering about unlit mode.
There is a way through the post-processing volume set to infinite. The exact method can be found in the Unreal Engine learning portal:
The exact method is taught in the course called:
“Stylize Renders with Post Process Materials.”
The exact method is in the chapter called:
“Flatten the World to the Base Color.”
As I am using Forward Shading / Forward Rendering, this method will not work.