Am I wrong to think that this may not be the best layout for your furniture? I just get the feeling that the loveseat should go where the sofa is and vise -versa. The loveseat on the other wall would not make the light switches such an issue and would fit better between the door opening and window. But I also see you have a shelving unit... A larger lamp to bring the eye up would also balance those windows out better.

You could put two curtain rods, one on each side or a connected corner rod at the same height (a few inches above the high window). It would disguise the weirdness of the three windows. The switches do seem awkward. Is there a better layout that would allow an end table or two with lamps?

Oh and yes some art would look nice over the couches. Do you have anything you can repurpose or you already like? I hate to recommend art to someone, since it’s so personal. You could get something large or do three smaller pieces. If you don’t like gallery walls stick with a single large piece or a triptych.