I’ve seen the other threads about “Recently Deleted” but the files (downloaded from my NAS to my iPhone) I deleted did not appear in Recently Deleted in Files app. There were no files there at all.
I had to delete and reinstall Infuse (thank goodness for iCloud sync!) to regain 6GB of space.
No, it was media files totalling 6GB that I downloaded from my NAS, watched, then deleted. But they didn’t get moved to Recently Deleted, as I mentioned in my original message.