Promising. If you have a working video file recorded with presumably the same settings as a reference, the internet claims repairing is not impossible …
For file repair jobs … don’t work with/ lose/ overwrite the original bad file, try repairs on copies only.
If there’s no success in sight at first, keep the bad file, a solution might come up later.
You may have the best options when transfering it to a (windows) computer. Even if the video file container seems broken the filesystem anyway may have finished its transaction and set the file state to valid. So you could copy it and first try a proper video player such as VLC. It sometimes offers a repair option if e.g. just the file index is damaged. Or you could try out if one of the freeware tools like Handbrake or Avidemux
can fix it.