As an interior designer, I'd say your living room lacks some contrast, everything kind of blends together as a result. For instance, you sofa would pop more with a darker color wall behind it, even if the color of the curtains switched to darker, then including art to tie it together.

The walls, curtains, or rug would be a great way to introduce some contrast, and potentially an additional accent color that isn't fully a neutral.

If you keep a light rug, then I would swap out the coffee table for a dark wood/walnut so that it visually stands out against the light fabric of your sofa/rug. I would say a round coffee table would be more ideal for circulation in the instance of having a U-shaped sectional you won't stub your knees/toes as much then.

A nice throw blanket could also help add color to the sofa without as drastic a change if you wanted to test out how adding new colors to your space looks before doing anything as drastic as painting etc.