[Nebasuke]

There are good devices for only music / audiobooks, but they're often aimed at younger kids. For example Yoto players (https://yotoplay.com/) or Toniebox (haven't used this one). Basically screenless, except for the number of the playlist.

You can use an app/website to create and upload playlist and couple them to your custom cards (so you don't have to spend money on buying loads of cards).