As a mockumentary, Popstar: Never Stop Never Stopping utilizes realism in the most absurd way. The whole premise of "Connor4Real" is taking pop icons to the extreme which isn't entirely realistic and yet the documentary style grounds it back down to reality that connects the audience to the film. This is used for a comedic effect, however this connection to the audience also emphasizes the key argument as well.
The film utilizes documentary style interviews and cameos to create a suspension of disbelief that Conner4Real is a "real" popstar. Most of the musicians acting in the film play themselves.
Not only does the film satirizes the Music Industry, but it also parodies the "Celebrity News" Industry as well. If the celebrities are going to caricatures then the people involved so deeply in their lives are going to be caricatures as well.
There are clips of Connor4Real's social media account where he talks directly to his "fans" and shows his, not so normal, lifestyle.
The film cuts these different outside medium's like interviews, YouTube videos, social media, etc. between observational style clips of Connor4Real and his agent.
While not as subtle as other pieces of media in terms of rhetoric, Popstar: Never Stop Never Stopping is able to show how ridiculous the lives of some celebrities are. Connor repeatedly does things or responds to situations that a normal person wouldn't do. Connor has a posse around him that basically says "yes" to anything he wants because they are being parasites to the musician's fame. His songs are filled with meaningless topics and lyrics that don't pertain to anybodies real lives except for a outrageously offensive and late-to-the-party song addressing the need for civil rights (The song was created in universe after the United States already legalized Gay Marriage). He goes on drug benders, makes bad deals with companies, and is overall an ass to some of the people around him. There's a clip where he supposedly went to the restroom at the Anne Frank museum.
One of the most ridiculous things that I think parallels real life is his whole relationship with "Ashley Wednesday". Even in the movie it shows that their relationship is really shallow and can be compared to some reality celebrity relationships and after a month they get married. Shortly after getting married they get divorced and Wednesday quickly ends up in a relationship with Seal.
I don't think I have to make a huge argument on how Connor's life is real similar to some stroies about real-life celebrities lives. They make big mistakes and it's all televised for us to see however they continue to stay in the limelight for the most part. Connor might be fictional, but he is based on reality.