I tried the iXpand drive and its a no go with the ipad pro 10.5. Sad. I'm looking at a WD Digital 1tb external SSD (USB C (compatible w/USB 3.0 & USB 2.0). You have to reformat the drive into Apple extended journaled format but that's not difficult.
There's a good youtube on all this by Fjordstrom You Tube - "IN_DEPTH: External Storage & improved Files app in iPadOS 13" https://www.youtube.com/watch?v=vR8C-VZv9-4
thats good. He also has a video "External storage support on Lightning devices? — iPadOS 13 on iPad Air 2" thats also good. I saw the apple lightning to USB Camera Adapter and think I'll get one. Fjordstrom tries a couple of "other" adapters which didn't work on the ipads.
Looks like we're on the edge of better utility for ipad pros in ios 13.
Hopeful but not holding my breath. Thanks