First scene after the OP is the Lip Sync Desert, in which characters frequently talk without moving their mouths (or while chewing food). Budget animation is budget.
Then they have a composer and arranger make a new song…before writing the lyrics. That's not how songwriting works, because it's much more difficult to fit new lyrics to existing music than it is to write new music to fit existing lyrics.
And yet, there's more. They finish the lyrics just a few days before the concert but act like there's no choreography to create and learn in time to perform—not that it matters, because of the record label change bombshell. If there is still no explanation next week how the other idol group stole B-Pro's new song… The writing in this series is truly, irredeemably, bad.