Additive Blending with URP Decals

Hi all, sorry for the inexperienced question, but I need to modify the Decal Shader of URP so that it additive blends with the surface on which the projection occurs.
I have the following image, which I could not/would not modify:


The result I would like is as follows (obtained through this shader GitHub - Harry-Heath/URP-Decal-Node: A node for Shader Graph that allows you to create custom decals. that exploits the Unlit one, so the blending mode option is available)

Whereas, with URP’s decal shader I get the following result:

How do I create/edit a shader (from the one created by Unity) that behaves additively like the one shown in the first image?

I’d like to use the one from Unity because I’m comfortable with the Decal Projector component, I think it’s already optimized properly, and I’m sure it won’t cause me problems in the project with future updates.

Thank you very much for your help!

You can output the map color to emission