ios 16.4 update deleted folder and contents on iPad

As part of the update, a folder and its videos were deleted. Additionally, the USB stick containing the videos will no longer connect so I can't copy them back. This folder is not sync'd to iCloud. It is over 20GB and primarily exists on my iMac, backed up to TimeMachine. Same problem with our 2 iPhones: 13 and 14.

2017 128GB iPad

Samsung Duo Plus 128GB and 256GB models

Is Apple gradually making products without the M chip obsolete?