Why set this story in the Alien universe?

Hear me out…were staring at the elephant in the room. RS wanted to make a standalone movie in its own right…then why didn’t he do that then? Did he crowbar Blade Runner into the Alien universe? No - in fact if he was going to expand on a universe with, it would be BR that I would engineer Prmoetheus into - not Alien. Seriously, and you can crucify me for saying it….the reason why noone answered the question of 'who the space jockeys were' was because NOONE CARED. It was a part of the mystery of Alien, a small enigma, it wasn’t the central exposition for the film or the franchise. So ask yourself is this some vanity project, or is the decision made purely on getting as much money as possible from us? Im sorry but I think the criticism of this film is fair simply because Ridley chose the path of how he wanted to tell this story. The look and feel, narrative, is completely anathema to the rest of the films….so it does feel out of place. This story would have been perfect in the Blade Runner universe if you ask me..which explored the same questions at the human level - but even better just as a standalone piece.