iPad not finding Dropbox folders, sharing from Dropbox to VLC fails

[BoppyTGA]

This is a new-ish issue and is specific to my iPad Air 3 - things work perfectly on my iPhone 12.

My iPad is a bit sporadic on which MKV files it will play via Dropbox. Others I have to share to VLC from Dropbox. Some of these files will go through the sharing process, then fail immediately after opening in VLC. I used to be able to navigate from within VLC to the files in Dropbox but in the last few months I have lost the ability to view any DB folders. I've disconnected and reconnected access to DB from VLC multiple times and the issue persists.

If I open Settings/iPad storage I can see the files but they are not viewable. I delete them to see if it's a space issue, but still no luck re-sharing them.

These MKV files play fine on my iPad when I move them from Dropbox to iCloud Drive but I pay a lot of money for Dropbox and I'd like the service to work as it should.

There have been other posts here and in other forums about the issue but I have never seen a fix. Can anyone suggest a way to use VLC with Dropbox on my iPad successfully please?