I know that there are alot of Spotify downloaders that download the metadata from Spotify and then download the audio from Youtube, but currently I don't use Spotify and I have my playlists on Youtube, is there any way to add the metadata to my songs or download them with the metadata?
yt-dlp (with --add-metadata) puts the channel name in the artist field and the video title as the track name. With --embed-thumbnail, it uses the thumbnail as the album art. This can all work, but only if your artist puts just the name in the title, and uses the album art as the thumbnail. The problem is when they don't.
On Android you can use seal. By default download the thumbnail of the video as cover, the channel name as artist and the video name as the song name. You can also download entire playlists.