Some camera vendors support a FAT interface over a Lightning to camera/usb port. This would let an iOS app read files off the camera using a document browser (and it works just fine). The files are huge videos, and in some cases take over 50% of the record time to transfer over WiFi.
One vendor unfortunately does not support this. They run PTP over their USB-C to Lightning cable, which means that Photos (or maybe Files, unsure now, I did verify it a while ago) on iOS can see and transfer the files. But my app is SOL - there is no apparent way to do this per Quinn.
However - suppose the vendor would get certified with Apple as an ExternalAccessory - my app could then access the camera through some method they would support.
This is going to be a tough sell, and just wondering what the minimal amount of technical work would be required on the vendors part to allow file retrieval.
