Question How to make/edit URP terrain shader?

I am making a game with stylized cartoon graphics and have made my materials/shaders using URP and shader graph. The problem is that URP's terrain lit shader has a lot more realistic lighting that doesn't fit the style at all. The main thing I need is a flat/sharp lighting ramp (see image below). Shader graph doesn't seem to work with terrain, so I don't even know where to begin. How to I adjust the URP terrain material so lighting would behave different?

 

I didn't need most of terrain features in my project so I ended up with converting terrain into meshes. So I keep initial terrain for editing and using meshes based on it for rendering with Shader Graph based shader.