The movie has a very interesting decision. There are multiple different names that the main character has. And all of them are unimportant. Therefor even the credits call the main character simply "The Killer". This killer is very calculative and cold. Similar to Fincher himself. And he does bad things for money. Similar to Fincher himself. ( Making movies isn't bad, distributing them with DRM is ). Perhaps the real name of The Killer is David Fincher.
There is also sometimes cheesy dialogue. But John David Washington and Madeleine Yuna Voyles are such skilled actors that it didn't bother me at all. They pulled it off.
There is a sub-genre of Horror films categorized by surrealism. It could range between totally insane films like anything directed by David Lynch all the way to something like Mandy by Panos Cosmatos, where it is kind of surreal, but also doesn't actually ask from the audience too much in terms of figuring out what is going on. "Beau Is Afraid" is more toward the David Lynch category of surreal horror.
But my favorite example of Steven's Spielbergness comes at the scene where David is trying to steal an Amphibicopter ( helicopter that can also go underwater ). Even the Flash Fair scene was rather tame compared to the two shots he did in the Amphibicopter scene. As the Amphibicopter rises in the air and asks "Destination?" and Joe answers "Manhattan", you see elaborate action stuff that is just so Spielberg. Yes! It's only about 10 seconds long. But damn! It's so Steve! The thing flies into the air controlled badly by the characters that do not know how to control it. The camera sweeps around the Amphibicopter in a perfect Spielbergian ballet. You have a flash of red light blinding you as you see that Joe is about to hit a sign! Cut! He hits the sing! The Amphibicopter falls for about a second but then catches on and rises again going though the elaborately built architecture of the future and through a holograph of lips. Exiting the Rouge City. He could just show the damn thing fly away and that would be more than enough. But he went the extra mile to make it into a proper action scene.