Room is a south-west facing room.

I don't know why you wouldn't stick with the Repose Gray that is everywhere else. Everyone doesn't have to have continuity, but if you like the color I can't think of any reason to diverge from it. Grays are usually good in southern exposures. I agree with you about Evergreen Fog and your sofa. I don't know exactly what color that red is, but anytime you put green and red together you're running the risk of making people think about Christmas. :-) I love Evergreen Fog as a color - maybe there is another room you could use it in? It seems like it would be easier to carry off in your dining room. Or use it in a bathroom or bedroom. It is a dark color, so I would only use it as an accent wall, or in a room with a lot of natural light. Dark colors can be cozy, however, if that's the look you're going for.

I'd stay with the Repose Gray and swap the Hutch with the wash basin stand.

I'd also stay with Repose Gray. For an accent, I suggest painting the railing and bottom post of the staircase in black and also replacing the fan above the dining table with a black chandelier, and accessorize the top of your hutch..

While you're painting, if you paint the risers white in your staicase, the oak steps with stand out and your staircase will look brighter.

I think Evergreen Fog could look beautiful in there. It’s hard to say, not being there in person, but I think it might be an interesting look and set the room apart. (And I know I’ll be the lone dissenter.)

Informative articles about it:

https://modandmood.com/sherwin-williams-evergreen-fog-2022-color-of-the-year-plus-dupes-sw-9130/

https://www.kylieminteriors.ca/paint-colour-review-sherwin-williams-evergreen-fog-9130/

I too would use the color you have on the rest of your first floor. Is it also what is on the staircase walls? This room is open to other spaces and the stairs, I think it would be an odd room in which to paint a different color. You are smart to think about the clash with the red sofa. If you are craving more zing or a deep green, introduce it by way or painted furniture, artwork, or accessories.

Since the Sienna Red sofa is in the room, I think the blues and grays are the wrong direction.

With those beautiful oak floors and oak pieces in the dining room, I'd try some of these shades to work w/the wood and the red.

Luckiy, Respose gray does coordinating w/the pink/red tones

(If you had a blue sofa, then the blue tones would be fine. but not w/the red)

you could go w/more of a taupe gray, but I think the dining room would look so pretty in any of the blushy/mauve tones. Make sure the white trim is also on the red end of the color spectrum. (polite white and Ibis white are)

if you want a grayish green, I suppose you could do that too (shown here w/Repose

Personally I think the blush colors look nicer.

why not get a few samples and just paint one of the walls with it?

South/West light...hot, introduces yellow into the room. Consider dark gray:

This is B.M. Steel Wool, a suggestion from Kylie M Interiors. It will work with natural light, your floors and a great backdrop for the sofa.

Your dark stair wall can be painted a brighter color...a green: