I would recommend placing a tall lamp on the end table. Treat the space from the right end of the sofa to the window wall as your space for art. When you place things on the wall above something, it needs to be centered on the item below NOT the wall. Make sure what you place there is about 2/3 the width of that space. I would opt for something colorful. Good luck.

The lamp is a wonderful idea!! Yes, a colorful/light piece would look great over this dark furniture. We just moved in and I've been completely stumped. Thank you so much!

I know you said the furniture can't be moved - is it because there is no room to do another layout? Could you turn the sofa around 180 degrees so that the back is facing the archway? And then put the chair in the corner by the window so it is opposite, facing the inside corner of the sofa - diagonally. Or you could maybe move the chair across so that it is facing the inside corner of the sofa diagonally. You could also get a tray, in a lighter color, maybe white to match the rug - to place on top of the ottoman so you can put drinks on the tray and have it act as the coffee table. Or put the ottoman in the corner where the big chair currently is, if you could move the big chair, and have it act as extra seating in case you have a crowd. Moving the sofa - if it's possible, will open the window area, and then you can hang drapes on the window, down to the floor. If you cannot rearrange the furniture, then maybe a big piece of art centered over where the space is between the chair and sofa. The move the sofa out a little from the walls - even a couple of inches would help, so it's not crammed against the window and the wall. Some big colorful pillows too - prints would be good. Or maybe large white textured pillows.

I should've posted pictures of the wall you can't see. There's a fireplace on the other side. Also, I ordered a distressed/off white coffe table to replace the ottoman! Hoping it will lighten the space some. Ill definitely pull the couch away from the windows to hang drapes! That's a great idea. Excuse the mess on the mantle we just moved!

Before I did anything, I'd fix that ceiling.

The room will look much more finished with drapes. I'd replace the end table with something more robust even if it cannot be any larger. The perfectly nice table is dwarfed by the large comfy sofa and chair.

Pull the chair up closer to the sofa otherwise conversion will be awkward.

Any room must have at least 2 light sources and more is better, going to be tough to fit them in. Perhaps use a picture light on a large framed piece of art over the sofa? A pole or arc lamp might fit in but seem a bit MCM for this room, maybe there are skinny lamps that would work.

Agree about no more dark things going in the room but be sure most things you add have some dark in them. Your new coffee table will need an accessory that has some dark color to tie it to the seating.

I would get a larger table between couch and chair and put a tallish, heavy lamp on it. I would put a floor lamp on the other end of the couch.....and I think your new coffee table will look good. Now a colorful ....red, yellow, or some bright color throw for laying over the couch or even the chair...get two pillows to match. A fairly large piece of colorful artwork centered over the couch...take your accent color from the art.