Not to be contrary ;-0 but I would center a large piece over the sectional and fill in with a table lamp on the end table, not more wall art. The remaining wall is fine blank. I would have a piece (or something like a diptych or triptych) that at fills in a great portion of the area above the couch.

Does the local artist have another piece available? Or is that out of your budget for now? If you have to find something inexpensive now, I'd consider a large engineering print from your local Staples. If you have an Ikea near you, buy the largest frame there you can afford and have an engineering print made to fit. Explanation of engineering prints: https://www.apartmenttherapy.com/what-are-you-waiting-for-inspiration-amp-tips-for-making-large-engineer-prints-207795 https://abeautifulmess.com/2016/01/try-this-color-engineer-prints.html

just a few ideas that I'd suggest. a plant in the corner where that little bench is. I posted two diff types, either would work. I gave you a side table w/a lamp on the other end. I like the idea of a pouf in this camel color to warm things up a bit, or do a stool or two placed in front of fireplace. I also like these shelves between the two windows. ( I don't know what furry dog is going to do with these,,,maybe have the toddler stand on his back?? lol. hang them well out of reach and they'll be fine. I'd put a few small plants on them. This will eat up that middle space) You could also take these teak decking tiles and attach a plant/pot onto it, and hang two of these between the transom windows. if you want a bench, do something like this in the wood. all of those neutral gray tones make everything seem very cool. add some wood and some texture to warm it up a bit. over the back of sofa do a cool piece of art don't hang them too high. (your tv is hung too high btw. ) and a rug for the sofa area A jute one would work too for the dining area, you could also do this jute rug like shown. for the wall, I'd do another piece of sizable art to hang on that one wall. This one has a larger wall, but look at the black and white picture. basically the same size of yours. you want something this big. Or, do a shallow buffet or console w/a mirror over it and some greenery, like shown here.

Not a pro: that is a long wall so make sure pictures are substantial, you don’t want small pieces that look like they are floating you want your pictures to look anchored...... when you buy online they have app that state show the item in the room. I have brought several rugs and their was an option to show in the room