Very difficult camera angle to analyze. It appears to me that he reaches with the front leg instead of leading with the front hip. That will cause him to keep his weight back and not build up as much momentum as he otherwise could. Therefore, he won’t get as much out of his body to throw with and that could cause him to try to make up for it with his arm.
I also noticed his back foot lifts off the ground instead of dragging. This is normally an indication that the upper torso is getting too far out front at release which also results in throwing more with just the arm. I think he may need to keep his head and shoulders upright (stacked) a bit longer.
Can’t really see any serious mechanics problems from that angle although I can’t see his feet. But, from what I can see, I would be interested in seeing a side view with the feet visible. It looks like he never gets his back leg extended, he might be too upright and his stride might be shorter than it could be.
One thing I can see that I don’t like is the way he finishes with his glove behind him (on 2B side) - not a good position to defend himself from a liner hit back at him.
Can’t see enough in the video. I look at lot of things at foot plant but I can’t tell when his foot plants in the video. He seems to have too big of a posture change. He might be lacking hip and shoulder separation but I just can’t see enough to be sure.