If this device supports to add local files for playing, then you could try to save Spotify music as local files and transfer them to your device for using. To do that, you need help from a tool Spotify Music Converter. By using it, you can easily download Spotify music offline and use them on your devices.
Thanks for the explanation here! As a music addict, I would like to listen to music with high audio quality. Tidal is almost meet my needs. But it won't allow to play the music on other platforms. Luckily, I found a tool called AudFree Tidal Audio Converter to help me and it works well.