Current Coby is probably getting treated like Hody or Chinjao by Post TS Luffy.
Lets not forget koby got the same haki training that he did .
Curent coby is probably around desrosa luffy without gear 4.
But oda don't show it well except the bounty and the weird chain things that seem unbreakable for some reason . Garp should hav epunched that thing a long time ago . Why keep him in chains ? Well maybe for shiryu to be able to do what he did in this chapter .