This is why I'm telling you it's not a hinderance. First of all, "too early" is not a thing. What? He grunts before the ball even leaves the other player's side of the court? No. And too late would be if he made a noise when the ball was on the other player's side of the court. I'm telling you he does neither. He plays rally balls without grunting, and he gives a heave-ho when he's going to change pace. Right before.
One thing that happened today, was that he cried "No," during a rally with Arnaldi. He thought his ball went out. Arnaldi played it, and eventually one the point. Alcaraz apologized for crying out during the point. Since Arnaldi won it, there was no hinderance. But he did apologize.
From what I saw, I don't think that Alcaraz in any way hinders with his grunting. If anything, he telegraphs the change of pace. It's just that the opponent is unlikely to be able to do anything about it.