After years of waiting, finally a serious company (ESR) launched a case, minimal, transparent, with air cushion, quality for its price, which protects the back of the iPad Pro 12.9, is lightweight and easily removable. It provides good protection for the iPad Pro 12.9, but does not add bulk. It also charges the Apple Pencil perfectly over the thin part of it on the pencil area, without having unnecessary port, which increases the device's size. I preferred the advantage of the lack of this port, which increases usability.
However, I would not put the tablet loosely in a backpack with this case, because it is quite thin. I would move it inside the Magic Keyboard or in another more rugged case. This case is ideal for me as I have a tempered glass screen protector.
For indoor use, it is really convenient, while also highlighting the beauty of the device through its transparency. I recommend it also because of its reasonable price, as long as you have installed a protective glass on the iPad Pro for the screen.
I hope the elastic perimeter part does not show signs of yellowing over time.