Hi,
I used to throw with a technique similar to yours and wanted to share a few things I found helpful. My understanding of this is still limited so please take this as a personal experience of development in progress.
First, what I see in your throw (a little bit exaggerated for clarity) is that the weight shift and arm swing occurs almost simultaneously and becomes a full body rotational movement from the peak of the backswing. You could try to find a more effective timing where the weight shift is initiated before the rotation and arm swing. This will feel like lag is created and makes the disc feel heavy.
To do this, I think it is necessary to first turn back a bit more with hips, head and shoulders. I found it useful to do the backswing exactly as if I was tossing a horseshoe underhanded, committing towards a pole in the opposite direction of the throw. Commit to this toss! Make sure to turn your hips, shoulders and head all the way, weight on left foot (RHBH), only toes on the ground with right foot. From there, start pulling the disc out of the backswing using your body weight, as if the disc was the handle of a heavy cart or a playground carousel. Done correctly this will get you into the position of the "door frame drill" or "loading the bow and arrow" drill. You do not seem to ever get into this position with your current technique.
Now the weight shift should pull the disc back into your center while your elbow bends (power pocket) and your weight is on your plant heel, letting you rotate on it. Sling the disc out using the elbow as a hinge and the axis from rear shoulder out to the elbow as a lever. Like a sling staff.
Most of this might happen more or less automatically if you throw something heavy, so that could be useful to experiment with.
Best of luck!
)
