Reading usb drive on ipad will not work
I have plugged a usb drive into my new 9 inch iPad 10th series but cannot see it when inspecting the Files app
iPad
Perhaps this will help:
Connect external storage devices to iPad - Apple Support
In particular note the specifications about the format of the drive. If you believe that the drive is formatted correctly, try a different cable or test the drive and cable on another device.
Regards.