The guy may have some legit issue.
I am no OL coach,to be clear. But as a DB coach, I can only assume he has a really poor balance issue.
He can come out of his snap going into defenders pretty well, run blocking and such. Balance is not an issue in run blocking as much because you are going forward out of your stance.
Alex struggles in coming out of his stance quickly to an upright ready position.
I had a DB have a similar issue, and he got "took" out of every backpedal. We had to move him to WR.
I don't know if my experience applies here, but it is all I can honestly offer. I don't think Alex is weak, soft, or lacking in talent. He just has an exploitable issue that has never been fixed, nor will it ever be fixed. . .like JJ's throwing motion or Lee's footwork.