New iXpand Flash Drive Keeps Crashing

My new and older iXpand flash drives both crash (all the time) when using my new Iphone12. The app opens up on screen but when i try and save a video and photo files from phone to USB drive it instantly flicks me back to the phone album.

how do i clear up the storage by this “documents & data”? i tried multiple delete and re installation of the app already, am a bit frustrated