Alternative ways to screenshot on iPad Pro

This support page details the only methods by which a screenshot can be triggered - either using the physical buttons incorporated within the iPad body, or an Apple Pencil:

Take a screenshot on your iPad - Apple Support

You can do the regular lock+volume but there are some other ways.

You can do Command-Shift-4 on your keyboard to automatically pull up the screenshot that it takes.

Or you can swipe up from the left corner of your iPad with Apple Pencil to take a screenshot.

I hope this helps. Have a great day.