Going off of the technology I saw in horizon forbidden west, My best guess is that it takes the light source shape and uses it to generate a shape primitive with a volume material and a blending mode set to talk to the cloud. It’s basically replacing the light with a capsule that has a material as bright and colorful as the light, which means it doesn’t have to do actual scattering math.
That’s probably how it works, but how you want to set it up I don’t know. You’ll need to make a material that talks to a light source and the volumetric cloud system, but beyond that I’d need to do more digging.