The script linked was just vibe coded. Ai isn’t that great with the ytdl params, yet. It’s obvious because if an LLM really knew how to use ytdl it would have used the input file option instead of looping through a file and invoking for each one.
When downloading multiple playlists, it is usually better to organize them into separate folders so the files don't all end up in one giant mess. You can use an output template to automatically create folders based on the playlist title:
yt-dlp -a playlists.txt -o "%(playlist_title)s/%(playlist_index)s - %(title)s.%(ext)s"