okay - from what I can tell...
Looks like you have a fairly nose down throw, which is good.
You might be getting some off axis torque in there though.
The disc is way too far away from your chest. When you reach back, you reach back with a bent elbow pointing the disc behind you. When you pull through, you pull through in an arc instead of straight back to front.
What's causing it is when you pivot, you keep your arm, torso and hips all locked together, so the disc comes through at the same time as everything else. The hop at the end just slows down your acceleration.
You need to start the pivot with your hips and have it drive your torso around. Leave the arm in the reach back and let it get pulled automatically by your torso as it rotates. By the time your hips have pivoted from back to front, your torso will pivot and the disc should then be around the center of your chest. At that point, just pull as fast as you can (and keep the disc as close to your chest as you can) until you're past the finish.
You may have to reduce your torso rotation so you don't over rotate and end up getting a late rip. As your arm speed increases, you can increase your torso rotation for additional power.
You can do that all from a stand still throw as well.
The x-step doesn't appear to be adding much to your power at all.
You have to imagine that your arm is a whip and the disc is the 9 tails at the end. When you bring the disc across your chest from the reach back, it has to unroll all the way down your arm until your wrist flicks open. You will have to curl your wrist in to keep the disc against your arm as long as possible.