I don’t see board and batten with the style of your room. Why not art? It can add or complement the colors you have already, and much easier to implement than am “accent wall”.

Might be helpful to see the entire room, as sometimes adjusting furniture can make a difference; for instance is centering your couch a possibility, as art above will feel off if it‘s not. Decide on the art format you prefer and then start your search.

I think art will have a nicer effect and save you all the trouble, but if you can’t center couch, it might be a better choice.

This may help regarding lamps.

Hang art. Add a picture light for a nice glow in the room. Add a floor lamp between the chair and sofa and dont over crowd the room with much else.