Doing each of these deletions separately may be substantially slower (unchunked, separate SQL requests against the sqlite db).

Perhaps it could:
1. Do the filter query, and store the resulting queryset (e.g. as `video_files_to_delete`)
2. Pull out the youtube ids: `youtube_ids_to_delete = [d["youtube_id"] for d in video_files_to_delete.values("youtube_id")]`
3. Delete the video file objects: `video_files_to_delete.delete()`
4. Loop over `youtube_ids_to_delete` and invalidate.