With regard to my previous post, I want to repeat that "you don’t use multiple render-engines at the same time, nor do you typically render “the entire scene” or even plan to do any such thing.
You use a series of renders, putting all of them into MultiLayer OpenEXR files, and engineering each one to be numerically compatible with the rest.
In one of the very-first (conventional …) photo workshops that I ever attended, the great Jack Dykinga said, “look at the light.” He kept saying that, over and over, until I finally understood what he meant. :yes: Don’t look at the scene that you’re trying to photograph: look at the light, because that’s what you are actually going to (try to …) capture, and then eventually project or print.
I naturally gravitated towards “darkroom work,” and still have a spacious darkroom in my house where I still love to go and play with exotic, dangerous chemicals. I visited the Center for Creative Photography (CCP) in Tucson, Arizona and got to hold (a copy of …) Ansel Adam’s original negative for Moonrise, Hernandez, and to compare a contact-print made from that negative to Ansel’s subsequent published work. The little lights kept turning on in my head, one by one by one.
I read everything that I could get my hands on by – or about – photographer O. Winston Link, who captured the “steam age” of railroading before it vanished. And who did so with thousands of flashbulbs. (“You only get one shot” at “a shot like this.”)
I assisted in (schlepped gear on …) a photo-shoot which captured the beautiful, sun-lit interior of a hotel … at two o’clock in the morning on a moonless night. I watched pros shoot photos of everything from coffee-cups to chrome. (Even today, there are specialists who shoot nothing but chrome, and automobiles. One of 'em quipped, “I specialize in visual sex.”)
When that happens to you enough times, words like “photo-realistic” fall by the wayside.
I rather suspect that many (Cycles …) renders of “real world scenes” seem drab and flat, and certainly don’t match the pictures in magazines, because Cycles is giving them perfect-truth (sic) of the setup that they used, while their reference photograph was not made that way. The renderer gave you precisely what you asked for – which is not what you were looking for.