Pull the sectional away from the wall a bit. It’s too tight.

Ignore the wall and hang a triptych just as if the wall was flat.

It’s hard to tell without seeing the whole room. How do you use your sofa? Is it for reading and relaxing, or is it mainly for TV watching — or for when you have guests?

Funny but I would definitely not to a triptych on the wall.

It is always easier to get ideas when the whole space is shown in the pic...for instance why the couch is pushed into a corner? Next to a Window?... and why it is so close to the wall?...what is on the opposite wall...is there a door..an opening?...an adjoining space ?...it makes more sense from what we see to treat the two walls separately..not as if it was flat...shelves will be difficult a unless they are high enough to not interfere with seating as is...

This is the full space. its a 1 bedroom apartment and the living space is about 220 sq ft. This is where we hang out, watch tv, have drinks with friends etc

This is a help...it seems to me that the most effective way to enhance the space would be to paint the recessed wall in a slightly darker shade..adding a little architectural accent...no shelves ...but definitely treating each section differently...pull the couch away from the wall a little... if possible center the couch on the wall change and use similar art pieces centered on each side of the couch...choosing art to go with each wall color but matching in size and similar in style...hang rectangular shape art vertically with top of art not too much higher than top of tv...this will enhance the higher ceiling ...add to a roomier feel in the room....the monochromatic color scheme will also add to the spaciousness..by not stopping the eye on every feature in the room...if you are a little more adventurous ...a bigger...more colorful rug ...and the recessed wall in a color from the rug...will bring a little more life and excitement to the space