>>724768485 (OP)
Deep Cut, unironically.
Squid Sisters' music is the worst of the three outside of the solo songs and they were boring as sin in their original game.
OTH have good music, but they're carried HARD by the S2 DLC and Artbooks building up their characters, songlist and dynamic.
Deep Cut had vastly better music from the get-go even if their dynamic starts off fairly weak due to the reduced emphasis on newscasts and the lack of representation in the Story or DLC, and their songlsit has only gotten better and better as the game went on. Ironically, their only bad track is the OTH collab.