Now we know why the new keyboards are so awful. They want to delight users by removing it completely for the new touch-only interface.
On the other hand, if we had to rely on keyboard cases, there might be better options than what we have today - e.g. I've heard a lot of good about this Razer mechanical iPad Pro keyboard although it's obviously very bulky: https://www.macworld.com/article/3115739/input-devices/razer...