No problem, I’m seeing it now.
The motion in the first clip looks pretty good to me. Can you do this any faster than this or is this a speed limit? If this is close to the maximum speed you can play with this technique, then that might be too close for comfort. Ideally you want some headroom between a speed like this and your maximum, so that you’re not really close to your limits when playing at this kind of tempo.
If this is close to the limit, then I would think about doing some experimentation to see if there’s any tweak to this that will produce an even faster motion. Changing to a different motion (forearm, elbow, etc.), changing your grip, etc. For example, have you ever tried a more Andy Wood style grip where the index finger is more extended and the fingers aren’t as curled under? Like this:
Sometimes seemingly unrelated changes will just unlock something for whatever random reason. When you’re in a rut, try not to hammer away at the same grips, motions, phrases, etc. In the short term those things have stopped teaching you anything. Instead do whatever you can to break out of the rut, even if that means switching things up out of your comfort zone.
The other concern is consistency. The part of that clip that starts around 10 seconds where you do it continuously sounds the best. Both before that and after that, are you starting and stopping as a way of trying to get the synchronization happening? Or are you unable to keep doing the motion continuously? If you’re stopping because the motion freezes up, then same answer as above: change something and try something else. See if some other motions or grips or picks or phrases or whatever, even one you don’t want to use long-term, work any better.
You’re going to need to be able to do the motions continuously when you work on things like hand synchronization. When you play really short fragments, it’s over and done so quickly that it’s hard to hear or feel if it was locked up tight between the hands. I can do short fast bursty things now that everything is learned, because the motions are all memorized. But beforehand when I was still learning, I couldn’t. I learned by stringing these little repeating fragments into longer phrases where I had a chance to hear/feel whether it was locked or not, and try to correct it.
The repeating figure you’re using here is a good one. Also try the four-finger chromatic one, either desc, asc, or looping as triplets. Try repeating diatonic scale patterns as well, a la Yngwie, Di Meola, etc. Throw as much variety at this as you can. Some of these phrases may simply work better right away, again, for reasons you can’t explain. And that’s fine. Take the victories where you find them.