I wouldn't add another rug. I think it will look fine just with the coffee table.

I would not add another rug. But, I would paint the room a little darker color for contrast with the sofa... a Taupe like the floor will warm it up.

IMO stacking rugs is not great amybe just a blck and white cowhide under the table . I assume you are renting or I would just say replace the carpet .

I would work on using your art work to inspire colors of additional chairs, pillows, throws, etc. in your room. And perhaps live plants near your window to add life to the room. Placing a rug on top of you rather thick plus carpet will be problematic…it will ripple and become a tripping hazard. Even a very large flat rug on a low pile carpet will move and ripple. (I know from experience).