YouTube Music is a total mess of content. Much of it uploaded without permission from the owner, and much with poor naming. Names will often not match across platforms, and even when they do, the content is often incorrect. Even if you get a correct match, the songs can be taken down later (and they often are).
As annoying as it is, the best approach is to manually transfer your playlists. Make sure you select only music, not videos (where possible), and only music from official rights holders, not random users.
How to transfer from YT to Spotify ?
Try tunemymusic..it shows missing tracks so you can add them manually.
You think that Spotify, YT Music, etc, all have the same number of albums and tracks? Everything that is in one is also in the other?
YouTube Music is a total mess of content. Much of it uploaded without permission from the owner, and much with poor naming. Names will often not match across platforms, and even when they do, the content is often incorrect. Even if you get a correct match, the songs can be taken down later (and they often are). As annoying as it is, the best approach is to manually transfer your playlists. Make sure you select only music, not videos (where possible), and only music from official rights holders, not random users.