Hi there agamcyclone,
Thanks for joining us in Apple Support Communities. We understand you're asking if your iPad supports a USB connection via OTG. We're glad you're here, and we can provide some guidance.
"Depending on your iPad model and external device, you may need the Lightning to USB Camera Adapter, Lightning to USB 3 Camera Adapter, USB-C to SD Card Camera Reader, or Lightning to SD Card Camera Reader (all sold separately).
Keeping that information in mind, you'll most likely need a compatible adapter. Have a look at this link to learn more:
Connect external storage devices to iPad
"External hard drives often require an external power source when used with iPad. If an external hard drive doesn’t supply its own power, and your iPad has a USB-C or Thunderbolt / USB 4 connector, you can use a powered USB hub. If your iPad has a Lightning connector, you can use the Lightning to USB 3 Camera Adapter connected to a USB power adapter."
Based on your iPad model, you'll want to take a closer look at the Lightning to USB Camera Adapter here:
Lightning to USB Camera Adapter
We hope this information is helpful. Don’t hesitate to let us know if you have any more questions.
Take care.