Can you post a few more pictures from different angles so we get a better idea of the context for this wall? Is that a piece of brown trim on the wall, chairrail height? How do you feel about removing it, or painting it the wall color so it disappears?

The piece of brown is a ledge created from the foundation.

How do you use the room? My eye is drawn to the wall because there is no coffee table or chairs for conversation. I always prefer to add items that have meaning to our family. I am a history buff so a lot of the pictures on our walls are historical scenes, framed prints I bought at antique shops. DH’s hobby is photography so a favorite hike to a waterfall is remembered by a large photo of that waterfall, bringing motion and color to that corner of the our room. I love genealogy so maps of the ares I research are arranged on my office walls.

I was thinking a mirror too I found this one on houzz.

You might look at moving the piece of artwork over to make it be over the chest. Otherwise you could do a gallery wall there as well. Here are some visuals for you:

Bright Transitional Refresh · More Info

Scandinavian Modern · More Info

The Van Buren Project · More Info