Since you asked: It is difficult to critique because you may hit differently against the wall than during match play. If so, ignore my comment:
On the forehand side (and in both series of videos) you set up well (though with off arm too far forward), but when you swing your hitting arm/elbow gets ahead of your UB rotation almost immediately. Most of your UB rotation happens after the ball is gone. I can understand that as an adaptation to playing a fast wall, but not letting the UB power the upper arm around (longer...) places a serious limitation on power.
By 'limitation' I mean this: Instead of using UB rotation to accelerate the upper arm, then exploiting your shoulder and arm muscles for additional acceleration into the hit once you are at least 45 degrees around, you are drawing on the shoulder and arm muscles almost immediately.
I've watched each several times and used freeze frame to check the relative position of your hitting upper-arm/elbow vis a vis your UB, so I'm quite sure of my comment, but I'm not sure you do this playing against an actual opponent when you have slightly more time to set up, adjust your position.
Maybe it is simply the fast wall that's forcing this reality? I'm reminded of the "ESR to lock the upper arm at the shoulder, letting the UB power the upper arm around" bit.
EDIT: Your speed volleying at the wall is remarkable. Are you also a squash player?