IMO you require something on both walls. I would add a narrow metal or wood console that extends at least as long as the three windows. Then a panoramic canvas wrapped print mount between the top of the console and the windows. Then add 3 square wall decor items,...........maybe carved wood. Not sure about that flower rug on the floor.

Thank you Beverly. I am debating over the rug. I just love it and have nowhere else to put it. I had considered a long canvas print and a bench. I didn't think about putting those iron pictures on that wall, I thought they would go on the other slim wall. Would they go all the way up the wall? It's a cathedral ceiling? Thanks again for your advice.

The plaques or objects don't have to be iron or metal, they just can't be colorful prints or canvas because that would compete with the other wall. If the plaques are 18x18 you can stack three on top of one another. Or here are some examples of other options.

Could be a stack of black and white framed prints like these below.

Great ideas with display of art horizontal on the wall.