I'm impressed. I was really expecting an ending with all of them performing together at a final live, only for Arika to jump onstage at the end and symbolically forgive everyone + be reunited with Nana in front of all the fans. But they actually saw it through and made it a (light) indictment of the idol industry: the group is just abruptly canceled, most of the members and like half the agency are arrested, and Nana's time as an idol is over - LyriTri was just too nuclear waste toxic to keep existing and for any of the innocent people to keep being associated with the name.
Side note: I found it really funny that Mimi had zero clue anything illegal was happening and was just completely oblivious to the huge conspiracies happening over the 3-4 years. I think it actually makes the central mystery more convincing versus if every active member was somehow directly involved in or witnessed the attempted murder and cover up.