I would not put anything behind the sofa

I think you need something with color behind the sofa as it stands now. Consider placing the sofa on a smaller angle to the corner. I know the corner is centered right now, but that leaves a huge area behind it that goes to waste.

I would put a floor lamp behind the sofa.

Brooklyn Floor Lamp · More Info

I agree with aileen. There's a lot of visual clutter going on with the vertical lines of the drapes, art, striped pillows, and the strong line created by the cushions of the sofa and the contrast of wall colors in the corner, which you're drawing attention to by placing the sofa in that location. The horizontal lines of the pleated shades add another strong linear element. The plant provides a multi-directional element that redirects the eye. Vertical pedestals would not.

If you're adamant on getting rid of the plant consider a narrow console behind the sofa with a lamp to soften all the vertical lines in the background and provide softer ambient lighting.

I like the neutral color scheme, it's very soothing but it needs a pop of color. Perhaps replace the striped pillows with a more colorful, whimsical design.

Would not recommend the pedestals. A bit dated. Get a better plant.