I don't see an improvement if grey. What about an ottoman cover in a color from the rug. Lampshade with more impact, etc.. What color is the rug?

Why not try an accent color first? Have you any right now cause I can't see.

It will definitely look different and darker and but also more modern. I do think you'd have to change the rug to a more modern, lighter colour too. Are those built ins black? Changing them to white will have an impact. Keep in mind that you have to walk around a sectional. Use your existing furniture and/or tape or paper to make the shape and size of the sectional on the floor and see/feel how that works

I like the yellow gray combo but not sure about the darker gray. I'd consider a lighter softer gray that keeps the airy feel but provides a bit of contrast compared to your present sofas.

I like the color here

Just some rug ideas for you, should you want to change it

I don't think you need to change your couch. Your living room color is very off. I would start with the mat first to go for for off white color to light up the living room.

I would keep the sofas, paint the black built-ins white, which should broaden the room considerably. I would remove the black mirror from the fireplace and replace it with original art as you have no real focal point now. The room is fine, but needs character. Once you choose the art, carry the colors across the room onto the couch with a couple of pillows.

I just got rid of my beige microfiber sofa so I totally get what you're saying. I think the gray sectional will work fine with the black built-ins but as the others said you may need to replace the rug. I'd put the sectional in the room before I decide that. Gray is such a neutral that you may be able to pick up the colors of the existing rug in throw pillows or even a throw that will make everything come together.

It's happened before that colors can show wrong. I think more photos would help. I can see some difference between beige of sofa and ottoman. Is sofa of a blush-beige tone?

Thanks so much for the advice! I am looking into a more modern area rug and will likely paint the bookcases white (unfortunately not built-ins). I will post 'after' pictures on this thread.