Looking for Recommendation on music player for children's room

Title basically. Right now my son is taking my phone at night and I’m playing him some soothing music to help him sleep. Obviously there are MP3 players that still exist, but looking on Amazon they’re just Android phones without the phone. There has to be something better out there. I don’t mind doing something like a NFS with music that they can then pick the songs and play music in their rooms. I know there are bluetooth speakers, but that only solves the speaker part and not the playing music. So I’m looking for any suggestions.

Thank you all!