Hello Piotr. First of all you have got a great hinge and a good base to work up from.
points to consider/improve:
- get your Set Up right, on each and every time you approach the bell: tension on hams, glutes, spinal errectors , lats(do the face the wall squat drill, and you get the sensation, what it has to feel like, when start swinging). It is that important: The Set Up IS the first rep
- you definitely have more lat engagement in the second vid, this much engagement is more appropriate to use in fast eccentric power swings (described in S&S), for the almost daily S&S style swings let the bell float on the apex, it is weightless there for an instance, you might try to just open your hands just slightly for that short moment, lat engagement more in a sense of shoulder retraction, than actually upper arm glueing (the infamous T-Rex swing). Because Your upper arms are that tightly connected to your torso might give you the (false) impression, that you braking with your hips later on the downswing. So let the bell float and keep the shoulders retracted. Stay longer in the straight plank position
- using a heavier bell could be instructive to your technique, in my opinion
You are on a good way, by the way to get critiqued through video analysis and your physique lost some of its softness. Keep going.