Not seeing an mage difficult for a non-pro but these are ideas for blank walls anywhere.

more....

Going to town with no one about.......stress is only on the walls for the moment. Hope you can pick up at least one idea from here.

Floor lamps at large scale will add height, symmetrical stacked art framed identically over the chairs, some large sculpture element on the wall above as a focal point set off center on the breakfront with a tall ceramic or glass collection to balance.The entire wall doesn't need to be filled. Think of it as a composition, and select larger scale things. Go look at the restoration hardware floor lamp lighting that could fill a huge space from its scale for inspiration , then diy.

Add photos for more specific ideas.