Caterpillars devouring perennial kale

I have a bit of a caterpillar infestation on one of my perennial kales. I have two and other is fine.

Nearly every single leaf has had a chunk taken out of and some entire leaves devoured. Have found packs of them on the backs of leaves.

I appreciate they are park of the ecosystem but it’s a quite young plant and it seems to be struggling.

Have removed all the eggs / caterpillars I could find and removed the very damaged leaves (not sure if that’s the right thing to do)

Any guidance on how to manage this and protect the plant?

Thanks!