Unfortunately, Apple doesn’t allow third party apps such as Playlisty or Amazon Alexa to connect to accounts that are set up as “Child” accounts within a family sharing group.
If you want to get some playlists from a child’s Spotify account and save them to their Apple Music account, you therefore need to go through a few steps:
- Install Playlisty on an adult’s device and link it to the child’s Spotify account. If Playlisty is already installed and pointing to another Spotify account you will need to sign-out of that account first and then sign-in to the child’s account.
- Import the relevant playlists to the adult’s Apple Music account.
- Share the playlists from within Apple Music (see https://support.apple.com/en-gb/guide/music/mus140a2e93/mac).
The child user can then access the shared playlists and link / copy them as required.