i have a very similar situation , and I hung an assortment of pictures in that space.

Hang up the guitar.

agree^ or i’d leave it empty

I already am making a gallery wall for above my couch, so not sure if I’d want another one and the same space.

I love a lot of pictures on the walls since ours is a ” second home”, and it is not my preferred style. The very high ceilings create a cold feel to the rooms, so I have enjoyed myself by searching through thrift stores for any picture that catches my eye.

I really dislke "gallery" walls since even the name is a misnomer. But why not another chair and a piece of art . Gallery walls often are just a mess of mismatched pieces that cannot be appreciated on their own and often family photos that I always think should be hung in my private spaces .

Perhaps a wall hanging. Your guitar is giving me 70's vibe. So, perhaps a "groovy" wall hanging would work.

Nothing. Less is more.

A tall plant? Also agree with other suggestions - hanging the guitar or nothing.

Maybe step back and consider the entire wall, as balance is key and suggest removing the little items.

You mentioned you didn’t want a fake plant, is a real one ok (?) and place by the window/ensure it has height. Chair moved to the right and pull out a bit to create a better connection + art and move guitar to other side. Add a few heavier pieces on the console that connect with each other.

With a few adjustments, the space will feel warmer and more inviting.

Take a step back and view that whole wall.
You may wish to visually distinguish the space by introducing a barrier element beside the fridge...maybe a narrow medium height bookshelf to hold
music books and related materials.
Then hang the guitar and put a comfy chair close by in case strumming is planned.
You may want to increase usefulness of the other chair and the lamp by placing some magazines and other books nearby.
Otherwise a tapestry hung beside the fridge could increase the artsy vibe.

What about a trio of tall floor vases.

Just a few examples.

Get a guitar hanger and hang the guitar in that space

Two ways I'd go here:

Option 1 - a symmetrical pair, one print either side of the TV. Clean and calm, works if you're happy centring the screen on the wall. Match the two prints in size and hang them level with each other.

Option 2 - a vertical stack of two prints in that empty space to the right of the TV. I think this is the stronger look for your wall, since the TV already sits off to one side. The stack adds height to balance the long horizontal screen, and fills the open area without crowding the corner. Keep the two frames close together (a few inches apart) so they read as one unit.

Either way, given your warm wood, rattan and greige palette, I'd keep the art minimalist - muted Japandi landscapes or soft abstract shapes in natural oak or slim black frames.

I run a minimalist wall-art shop (Inprint Designs) and wrote a guide showing both these layouts with exact sizes and spacing - hope it helps!

Considering the whole wall:

AI used identical chairs and lamps on both sides, but they wouldn't have to be, and variation would actually be more interesting. (This also assumes you are a versatile musician and have a bassoon lying around. Doesn't everyone??)

I’d actually use that empty wall space for lighting rather than another piece of art or a mirror. One moon-inspired wall light could look really beautiful there — it would fill the space without making it feel cluttered, and the warm glow would make the whole corner feel much cozier in the evening.

I recently compared 8 very different moon-inspired lights, including wall-mounted designs, and your space immediately made me think of one of them:
https://youtu.be/g-R98L8EdII