This is the closest thing I can find.

Mighty Vibe Spotify and Amazon Music Player - Bluetooth & Wired Headphones - 1,000+ Song Storage - No Phone Needed - Black https://www.amazon.com/dp/B07KJY8QMK/ref=cm_sw_r_apan_i_J5NBT7ZP137XKE3YWRRV?_encoding=UTF8&psc=1

It doesn't seem like the kind of thing companies work make nowadays when an old phone without service can use offline Spotify. It's really only a thing to exist for getting through a phone rule loop hole.

I think you can try this: https://www.amazon.com/Mighty-Spotify-Music-Player-Zazzy/dp/B07KJY8QMK