@matteo, you have good power! Your setup is good, nice and tight and aligned. You grip is fine, back position looks great, shoulders stay aligned left to right. All good.
So I don't see any problems or errors with your swing but I see some things that could be improved.
I agree with
@CraigW, hinge deeper, but here's where you could put the focus. Watch your swing at .25 speed. The upswing is good, but you will see something interesting on the downswing. Your knees bend first. Then the bell swings down. Then your hips flex in response to the bell swinging back. Try to coordinate this movement better -- stay planked as the bell starts to fall and keep the knees locked, quads tight, kneecaps pulled up until the bell is halfway down. Then, all together and very quickly, move your body into the hinge. Do it as if you are getting ready to jump. Hips and knees flex together when you are jumping, right? Do it that way for swings. Then you will feel a better loading of the hamstrings at the bottom of the swing and the timing will be better to explode back up. On the upswing, focus on producing force into the ground, like when you jump. The more force you feel at your feet the more effectively the bell will fly up.
The other thing is relax the arm and let the bell pull your arm straight - it's a little bent at the top of the swing, and straighter is generally bettter.
Hope that helps... let me know if any questions. Very nice work overall!