Hey Fabian!
So your backhand overall is looking very nice, you have good acceleration through the ball and using the lower part of the arm really well and getting your body behind each shot!
I can see you have a nice contact on the ball too, I think just a couple of small things, trying to slightly relax your arm and just making sure to focus on getting the spin, this is when I felt you hit the best shots. Also just making sure you contact the ball quite close to the body and not far away, I think if you just focus on these 2 things it can improve even more, especially being relaxed in your arm and the grip.
But overall as I said very solid and strong technique, not many bad habits at all! Dan 🙂Â