Any ideas?
Have you used the ipad recently? I’m using my ipad now, and my iPad shows battery usage.
I suppose you have tried toggling between usage and activity? That has worked for me in my iPhone in the past but currently running Beta 4 of iPad OS 13.1 on mine so not much point in comparing. Needless to say it's working fine on my iPad.
I use it all day every day. It is my main reading device for newspapers, magazines, books, forums, etc. I used it so much yesterday that the battery went from 100% to 25%