About metadata, we are able to retrieve proper "music" metadatas when you have connected YouTube Music instead of YouTube. If your playlists are mainly audio-only, we recommend you always use YouTube Music on Soundiiz.
Also, on Soundiiz, if you are connecting to the YouTube Music platform and retrieving the video's name, we can also retrieve the artist's name. That could be very useful if you want to export to another music service or a file (CSV, TXT...).
And finally, be aware that YouTube and YouTube Music share the same user library. That means a playlist created under your YouTube account is also available on your YouTube Music account as long as you use the same Google account.
What about Watch Later and Watch History?
YouTube does not make these private lists available through its API, so Soundiiz cannot display, transfer, export, or synchronize them. Read why YouTube Watch Later and Watch History are not available in Soundiiz.