Connecting camera to iPad by USB-C cable: cannot access images

I have a Sony A7 III and I have connected it to the 3rd Gen iPad Pro as shown in Apple's photo using the USB-C cable that came with my iPad Pro 2018. The iPad does not recognized the attached drive as it should.

Things I've tried

*Changing the USB mode on the camera from "mass storage" to MTP

*Looking for the camera in the Files app

*verifying that I can see the photos when attaching to a computer via mini-usb.

*Updating the camera firmware

*crossing my fingers

*doing the same thing again and again, "just in case"

Please advise!