I made it through three episodes of Mozart in the Jungle and have had plans to see Tar cancelled three times. But the backstage comedy (literally) you're looking for is Noises Off by Michael Frayn. It's about theater and it's best to see it on stage (for reasons that will become obvious). The film isn't bad because the casting is so good. Frank Rich, theater critic for the Times for many years, said it was the funniest play written in his lifetime.I saw it in a theater back in late October, and I thought it was glum and pretentious. The beginning where Tár gives several overlong speeches was especially insufferable. Things improved slightly when the actual plot started to kick in, but overall I could not wait for it to be over.
I would love for someone to come along now and make the opposite of Tár: a low backstage comedy that depicts how the practice of classical music is just another ridiculous corner of show business. Come to think of it, is that what Mozart in the Jungle was? I never saw it.