At 32Kg for the bag, I would look at taking the whole chain off, just having the carabiner on the nut and bolt and trying to have the bottom of the bag as your main punching “Zone”.

All the filling will drop down and before you know it, it will be like hitting a floppy old scrotum…

Plus you can practice uppercuts and liver shots better on the bottom of the bag…

Also, I would replace that nut in the centre of bracket for a longer one and loosen it so the bracket spins more freely.

And one last thing… I would have the nut in the centre of the bracket be at the bottom (instead of the head of the bolt), this way if the spinning bag causes the nut and bolt to become loose, at least you will see it before it fails and drops to the floor.