The problem with biopics like this is that a part of your brain will always be judging how good the likeness/voice is instead of experiencing the actual story. They ought to find a way to depict pop stars a little less conventionally, perhaps as a CGI monkey?
You forget how bad normal people’s music taste is. Had a drink with housemates and their favorite songs are a slow sad dramatic version of Mr. Sandman and the Disturbed cover of Sound of Silence