Joker 2 is one of those movies where it can feel weird to criticize it because you end up on the same side of other people doing so for the worst reasons. It was the same with the Wiig Ghostbusters.
I am sad to see Keener and Coogan in this so far. It is easy to see why these films are so popular with a certain sect of people. If all you have seen are bad comedies and superhero films this has the veneer of sophistication and depth. It is Chili's if all you have ever had is Little Caesar's and McDonald's. The musical thing is just a work-around for the fact that they are stuck in the prison and since they decided to make it look so drab they had to have a way to change the setting for some flavor.