The USB player interface has been pathetic from day one.
Five years ago I asked TESLA for USB playlist support...
Speaking of playlist support, I have recently (mostly) solved my long standing problem of playlist support.
After some research, I stumbled upon this MUSCONV app,
Transfer Your Playlists, Albums Between 50+ Music Services.
MUSCONV is a Windows app (fat client) that converts (and syncs) playlists from various sources.
I used it to transfer my PC based Playlists to TIDAL.
I use JRiver Media Center as my music manager on my Windows PC.
I exported each playlist in CSV format from JMC and then imported to MUSCONV.
MUSCONV does a good job of fuzzy searching for songs in your playlist on the destination service.
It uses 4 fields: Track, Album, Artist, and Duration to search.
Then I transferred the newly created playlists in TIDAL to Spotify.
I have both. TIDAL for HiFi, Spotify to sync with my son and easiliy throw music to network devices like TVs).
MUSCONV supports over 40 music services, including Apple Music, YouTube Music, and Amazon Music, etc.
It is a bit temperamental, but it works!
Using TIDAL, I now have all (99.99999%) my music at a minimum of CD quality in all my cars (Teslas), Master quality on my phones and PCs, and Dolby Atmos Music in the Home Theatre (via the TIDAL client on Amazon's stick. Roku's TIDAL client does not support Dolby Atmos) .
I would use USB music in the car if the player was better.
There are so many features that I miss in all these players.
One that I will mention, we had on the first hard drive based RIO car head unit was called "pivot".
RIO was a LINUX based head unit from England in 1998, one of the first that had (two) laptop hard drives and FLAC support.
While listening to a multi artist playlist on the RIO you could "pivot' from that song, out of the playlist, to the next song on the Album the song came from. Or the next song from that Artist... Or... Or...
There are so many features that could be easily added to make a capable music player...but alas :|