Never a fan of hearing how a teaching pro has "dismantled" anyone's swing tbh. Some of them have an idea that there is a perfect swing that they can teach to anyone and that simply isn't the case.
One of my workmates plays off 11 or so, and after playing for nearly 30 years he went for lessons and the pro basically told him he was doing everything wrong, including the way he gripped the club. He went through the same as you are and ended up just going back to the way he used to swing it, he went for 2-3 months with zero enjoyment from the game.