Amen to what Anglophilia said. Do not--repeat--do NOT buy "wall art" online! That's your Living Room, not a dentist's office. Put something that makes a statement about you and your history or something you love. I can walk past Rittenhouse Square almost any day and buy a reasonably priced original oil or watercolor painting from an artist who is standing there painting. I bought a watercolor from an artist in Hyde Park while on a trip. Go to art shows, college student exhibitions, First Friday gallery nights (here in Philly), etc. Wait for something that speaks to you. You'll support a living artist, get a good story, meet new people, and when you have guests visiting, you can have a conversation that doesn't end with "...and they gave me free shipping!" Oh, and cool room. Except for the coffee table; I'd trip over those splayed legs. Again.

great advice upthread I'll try to be short, probably repeating several people: -get rid of the white console next to the fireplace/look for smth else instead if you need it there for function -think of other window treatments. curtains? woven blinds? roman shades? any of these will look better. move your sectional a bit from the wall, both to allow room for window treatments and because furniture generally needs at least couple inches to breathe..that wil also make room seem larger -you already purchased the ottoman in the same color and style of the sofa..off white, right? well something different would be better, but it's okay..buy a throw, fold it and put there to break your lines a bit. tray is great too-both for function and beauty. you'll appreciate it when watching this TV -I liked reading how your wife gets her art:) okay..so if there's no real room for other suggestions(I'm also prejudiced against mass produced canvas art..maybe she can be talked into a print instead?..)..put that art there first. Make sure it fits-seems huge?.. Say you go for that a very similar art, you have there-a bit of white, black, brown, indigo blue, fiery yellow white and brown you already have in your room (btw like your furniture) pull your other colors (in pillows and throws and accessories) from that art -deep sophisticated blues, golds. can be metallic accessories (like vases or flower pots?), can be softest fur pillows can be velvet, can be knitted throw. everythhing you buy-make sure it's a different texture..leather is sleek you've got enough of it. Speaking from experience-I also have my fair share of leather:) then look for a big ticket items like curtains and a rug. (or simultaneously..just keep your general scheme in mind). you can decide to make them fairly neutral. repeat the color of the furniture, just different material of course. or go for one vivid deep color but make it a shag rag for example. Don't try to match pattern to art..art has a mind of its own. Look at the room as a whole..what does it ask for? and know yourself of course..say I love many rugs but I don't like to clean them lol. You know whether it's high traffic area, what your habits are, and whether you'll be sad for 5 min if the rug will have spots and then get over it, or will be sad for 5 days. when you buy a side table try, again, to introduce another texture, just different material in this case. maybe wood. maybe ceramics(garden stool?some of these look really modern). every new material you bring creates dimension. Dimension is something you look for when creating spaces. Why? well that what we've used to. Ouside always has it. Even when it's a desert or an ocean. It has depth. we need to recreate it with all sort of ways and means that are availiable to us.. Good luck! will be a cool room edited because of thousand typos..))

Buy a second piece. Same size. Or find a larger piece you love. Or paint over an old canvas. Sand a bit if it has lots of texture. Prime with any latex, doesn't have to be white...leftover primer is great for this. So are sample pots. If you know any young kids, have them do it, restrict their palette to the colours you want (if you must). http://www.likemerchantships.com/2009/04/use-what-we-have-ugly-craiglist-canvas.html and https://theartofsimple.net/what-to-do-with-bad-paintings/

I think an abstract landscape/water piece, with some color, would look fabulous there … and play into your wonderful views. It would also bring warmth in, while keeping with the very modern style of the room. I’d look on Etsy, on gallery sites, Ebay, and/or visit local places to find a piece that speaks to you. This is a prominent spot — I wouldn’t buy a big piece of generic wall filler. Art here could be the soul of the room. https://magazine.artland.com/top-10-landscape-artists-in-modern-and-contemporary-art/ I do like the idea of three b/w prints you posted — it brings to mind water movement.