ok, step by step to free up some space - I think this will work from within a locked /e/ recovery after you enabled adb in the /e/ recovery menu - How to mount encrypted /data partition in recovery mode? - #14 by tcecyk - the user had similar circumstances (full disk)
if you read it to the end, the user looked at file size and group ownership - by seeing “media_video” inside /mnt/userdata/media/0/… it was a sure bet to be a video file.
full disk was an issue in this thread too… makes me think damn Android, retain some space buffer! Bootloop on FP3, after disk size full (maybe)