Off the top of my head, I can't think of an american movie with a main character who is an author and the film being a back and forth between reality and the fictional world of the author that riffs on reality. I have not seen it, but The Lost City with Sandra Bullock plays out like that I think? Anyway, for anyone who knows French cinema of the '70s the movie that springs to mind is Le Magnifique. The problem with Argylle is that it mixes Le Magnifique with The Long Kiss Goodnight and these are two ideas that do not mix at all. Since Vaughn also complexifies the script to the max with triple agents double crossing each others and abandons all idea of realism in the action scenes, it all becomes a big steaming pile of wtf.