Sofa is small for that wall, usually art size recommended is 2/3 the width of the sofa. I would center the sofa on the wall.

art.com

minted.com

greatbigcanvas.com

How are your photography skills? Perhaps you could take a few photos (landscapes, places you’ve been etc.) to complement the art you already have and create a gallery wall behind the sofa with your own photos.

Look into a local artist or art gallery. Some colleges have either their own art galleries or art departments. Look online for them or call them up and see what's available. If you are creative, go to an art supply store and get two 3x4 foot stretched canvasses. Get some acrylic paint and create some simple abstracts (if that goes along with your style). Put in top youtube search box "paint large simple acrylic abstracts", and see all the ideas. Below is a creation that I made.

Similarly? a light touch in art --

"Boatman on Pond, 1862" by Jean-Baptiste-Camille Corot, 44"x29" · More Info

"White Paradise" Black Framed Art Print, 44"x32"x1" · More Info

Mat = 2.5" wide. Frame = 1.5" wide.
Photographic Print with Standard Black Frame entitled 'White Paradise'. Photograph of snow covered trees around a blue-green body of water and a flock of birds flying through the cloudy blue sky

for $145

"Cerulean waters" Canvas Art, 48"x32" · More Info

Posting because idk what's personal for you - maybe you like a certain animal or flower ?!

"Animal Silhouettes I" Floating Frame Canvas Art, 26"x26"x1.75" · More Info

"Geo Animal III" Floating Frame Canvas Art, 26"x26"x1.75" · More Info

The artwork now above your desk would look perfect centered above the sofa imo. Could you do something dif on the desk wall?

Ha! I knew I recognized the Rotter piece (have one by him as well)! Have you tried hanging it above the sofa?

My daughter has just started a website where you can commission artwork or buy what she’s already done. EmmaFurtado.com. It’s worth a look! Thanks

These are some samples