What a coincidence, i am also making a Nothing themed local music plsyer and will release it soon. Looks good, great work.
I am trying to make a clean UI with new Nothing design language. Bringing in QoL features from apps like Spotify. Here is how play screen looks:

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I have tried it and love the lyrics implementation, it’s really neat. (How did you get around API limitations?) But i think some UI elements are too squeezed and small. The miniplayer has the current time and track length in it but it’s so small, i think it can be removed or just current time would be enough for a miniplayer. It could certainly benefit from a simplification.
The dot typeface is also very nothing coded but i think it struggles when downsized (the mini tags under the album arts showing sound file quality) and could use a different text maybe. The serif + dot font are thematically too different and i think having them interchangable for headers would work better.
Functionalitywise i haven’t encountered errors but the app didn’t parse all my local files (i have around 6000), i feel like sorting can also have its own button as well. Very good foundation, overall i think simplifying some parts can really make it more intuitive because some areas are too information dense compared to others.