I have this sitting area that I'm having trouble figuring out how to decorate. I don't like clutter, but it feels too empty. I'm particularly having issues with the empty, but unusable, space behind the circular couch.

I had a couple of ideas, but I'm not confident that any would look good:

• A lamp in the corner opposite the plant. I'm worried that this will look too symmetrical. The plant can't move (or needs to be replaced by something the same height) because it's hiding a sensor in the corner.
• Darker window treatments. I can't figure out what color would look good here; black to match the baseboard seems too dark. Gray to match the couch would be too same-y. Maybe light gray?
• Dark sideboard either below the left window or on the left wall. Both locations feel off to me. Below the window seems like it would leave too much empty space to the right, but I'm also not sure about putting it behind the couch.
• Art on the wall beside the left window. I'm worried it will look weird because there's too much empty space on the lower half of the wall. If I have a sideboard there, it might look too cluttered compared to the opposite wall.

Does anyone have any recommendations or ideas on how I can make this space feel less empty?