I’ve had my 2018 11” iPad Pro since February of 2020 ... no bends, even when I took it with me to travel inside a backpack with other items pressing on it. Mind you, I have the keyboard folio case on this iPad at all times as well as it’s in a sleeve and another zipper case when not in use. In the end, it all depends on how you handle your devices. I don’t see any sort of “bend” on any side of my iPad Pro in the almost 1 year of owning it.
After putting on a case, a sleeve and a zipper before storing in a bag, I’m not surprised the device doesn’t bend