Possibly Japanese beetles. Not many other insects bother smoke bush that would skeletonize the leaves that thoroughly.

I’ve seen some kind of larva that looks like tiny, slimey poop feeding on cotinus leaves Also on sumac.

I'd wondered about Japanese beetles. gardengal48, Do you know if the tree will fill out next year, or if this damage is permanent?

"tiny slimey poop" sounds like pear slug. Not actually a slug but an insect larvae. They feed on many deciduous plants.