a few features I would like to see,

Boombox continues playing if you move it around your inventory with the cursor.
Curio support to listen while the boombox is in a curio slot.
More disc storage in the boombox.
Place/pickup the boombox while still playing the music.
Sophisticated Backpacks support ...
not sure if this one is for Etched or Sophisticated Backpacks to implement.
Sophisticated Backpacks jukebox upgrade doesn't accept etched discs

(I really like the boombox)

not sure if you are updating for forge 1.18.2 anymore, but that's the version I'm currently playing with my friends on. would love to add these features if they happen.