About the Shahed-136, there's not much available online but I found this:
Comparing it to similar Chinese loitering drones, I think the warhead would be around 25kg. So pretty substantial.
The engine apparently is sold on aliexpress. I think most of it is made in China apart from the warhead and airframe, which is pretty easy to construct. If it was up to me I'd have the warhead made in Russia as they know what they're doing and it'll be safer transporting it.
Much bigger warhead (5x), plus the fuel itself is an explosive. KUBs are battery powered. It should be able to take out anything on the battlefield in one hit.