Jack, had a similar problem some time ago which helpful Ppruners provided a solution.
Had many files backed up on a Seagate hard drive which I wished to access from a new iPad; avoiding lengthy transfers via cloud etc.
A cable link to the iPad was not possible because the hard drive required power; even after the latest Apple software update, direct transfer might only work with a flash drive (Apple advice).
A helpful solution was to connect the hard drive to an adjacent modem via USB - BT modem, and then transfer files via normal Wifi.
The free 'File Explorer' App identifies the hard drive as BT HUB, and the drive as 'usb1'. Thence files are accessed and transferred conventionally.
Had not considered video, but todays experiment with mp4 and wma on the drive play with acceptable quality via Wifi.
Type of USB etc - beyond my knowledge - plug and play (or not).