He needs a post game, that is what will make him truly unguardable. Right now he's a finisher that relies on others to get him the ball, he's a lot like how Anthony Davis in how he scores right now. Ultimately you want him to get a go to move in the form of a hook shot or a turn around jumper on the baseline, shots that are just unblockable and looks that he creates for himself (and others).
Obviously that wont happen soon since he needs to gain weight to utilize it, but his goal should be Pau in the post, while still keeping his 3 and stuff off the dribble off PnR.