This is probably my favorite idea yet, give every beetle their own song! (Sorry for the workload on this one DrMurderizer but you could def do it). But anyways each beetle would have their own theme that plays when looking at the beetle in the beetle overview section, and beetle mastery menu (When that releases in the future). It could also play the best part of the song when you score a goal, (Or during the score replay if that gets added). I just think it would be really fun and add some more character to them.
Plus what are the beetles listening to with that headset accessory? Their theme of course! (Maybe the headset accessory could play the beetles theme subtlety in the background?)
I was thinking of a couple examples and Goliath could have a strong Sumo-wrestling type beat with gongs, cyborg could have some synth wave or eurobeat with that robotic feel, fungus could have that chill lo-fi feel, there are a bunch of different ideas to play with! (Ideas after the post, Potato with a more farm-inspired tune with a harmonica and banjo)