Compile All Playlists that already exist Into One Playlist / Add to Liked Songs

[-Melody-]

I have tried moving all my playlists into playlists manually but even with doing that I still get the pop up "An Error Has Occurred" when using "CTRL+A" To select all the songs to add to my liked songs.

My suggestion is a way to either add a stationary playlist like local files or liked songs that keeps any song you have added into a playlist/liked or a way to select multiple playlists at once to add into one playlist rather then having to select the playlist individually to add to another playlist.

OR The same method of being able to just select multiple playlists to be able to move into my liked songs - my goal here is to have all my music in one playlist- which id now like to be my liked songs - I can do it manually but think it could be a convenient idea if possible