Is there a cable or splitter that will allow you to charge your iPad Pro while using the lightning port to plug in a non powered usb controller? If the iPad slowly dies while it is in use that is not very useful.
Yes there is. Apple sells a dongle for the lightning port that splits out into 2 ports (lightning and USB).
$39 Lightning to USB 3 Camera Adaptor
Yes there is. Apple sells it. It’s a combo Iightning port/USB