If I remember correctly, the new OSL color correct map has an option to color correct only certain hues, might be worth trying if you're on Max 2019+... not sure if it really does this, though.
Another thing, but it depends on how true to world the new sky model is, the sky is always darker in opposition to the sun. It's the same in your example, the sun is behind the camera, lit objects are brighter causing shorter exposure/closing the aperture and making the sky darker/richer in return.
One important aspect to remember is tone mapping and color processing. The blue will vary depending on camera manufacturer/model so the result of what your camera 'sees' is pretty much an arbitrary decision made by the manufacturer. It can't really look the way colors are because they are interpreted by the camera's hardware and software. Even if the 'spectral color' in the photo and the sky map were the same you would not get the same output from the renderer unless all the color math is identical. That's why tone mapping and LUTs are such a vital part of the color discussion.
However, I totally see why you want to do this... Yeah, keying out certain hues and being able to color correct them is important every now and then.