Dynamic Clouds, and in the sense I believe you want, are volumetric yes?
Skibidi Clouds, An attempt at fully volumetric 3d cloud in roblox - #7 by tin_nim
(This is some sort of shader I believe)
I believe this one would help you the most.
For reference, I’d avoid using billboard guis for a large amount of instances due to the amount of drawcalls involved.