On move 20 you're better because your opponent has hung material. That being said, generally in the exchange ruy the bishops are an asset, not a liability, so talking about how he's "lost" one of his knights is sort of misleading.

(Although he's about to drop material for real, for what it's worth)

I think you're patting yourself on the back too much. At move 16 you have a strategically lost position. Your knights have very poor squares, your king lacks protection, and you're down a pawn, to boot. Black frees you by capturing on g5 - a huge tactical and strategic error.