You can learn the drills and improve technique which is improvement. Gains are relative. However, athleticism cannot be taught or overcome at this level.
I don’t blame the coaches for recruting him, you can’t coach size and his lack of experience was the perfect cover for lapses on film. It is rought to tell with a guy that size going up against 220lb juco defensive ends. But the choice not to cut bait when it was clear in 2019 that it was never going to happen is troubling.