Where? You posted pics of a subpar back. His back detail ends mid back, after that it's wrinkles and a missing mid lower back. And his delts overpower his back. All the great backs from Haney on, all had complete detail, top to bottom, and their Delts disn't overpower their back. The best genetics don't get involved in bodybuilding. There is no money in it, plus there is a stigma. Just the reality one must face.
I don't agree. Aesthetically he is miles ahead of Kai. His arms are bigger, bigger pecs, bigger shoulders, better proportions and taller as well. Kai looks like someone slapped a torso on another person's lower body, especially from the rear. His back is crooked from the rear.
Have you ever heard the expression a house has "good bones" and therefore worth improving? Well, that's Justin. He has a lot to work with and needs to add a little mass here and there but the proportions are there.
You don't see it, I do. It's subjective.
But I can see with all your typos in your last post that you are getting emotional.

Take a deep breath and relax. It will be all right.