Only Spotify software can play the Spotify streams. There are no third party apps to play Spotify. Hardware players that stream Spotify use software developed by Spotify to hook in.
Regardless of the source of the digital stream, there's no software that can restore the data that is lost to file compression (and sound better doing it.)
I didn't know Spotify offered 320k resolution, that's good to know! I wonder if it's available on family 5pack subscription.
If Spotify 320k isn't good enough then try Tidal HiFi. It streams full 16/44.1 resolution via flac lossless compression. People say the Tidal GUI isn't as good as Spotify, but I find it to be OK (once I got used to it, and avoided Spotify app for a while.)
There is usually a "First 3 months free" offer going on Tidal. Search AC or goog for details.