A friend of mine has a daughter who is too young for a smart phone, but he still wants her to be able to listen to music on the go. I found the following devices using spotify. Have you used any of these or do you have any alternative suggestions?
https://www.tunepat.com/spotify-music-tips/portable-spotify-music-player.html
Edit: found what I was looking for. https://bemighty.com/
Yes. I used to give my old phones to my kids for entertainment. Nowadays it seems like music videos are as prevalent as mp3s, so you need a decent display as well.