Because you have so many square sized items, I would use an oval, the one I'm showing may not be your choice but it shows the look and size. https://foter.com/oval-coffee-table-with-storage

ThT coffee table seems too delicate compare to the sofa and other pieces to me.

Use a round coffee table with your L shaped sectional.

Is that a marble top? It doesn't seem to relate to anything else you have in the photo, so I would keep looking.

No to the coffee table. Keep the rug, it works with the sectional, but reposition it so the front legs are on the rug.

Other suggestions:

West Elm

Wallpaper over chair rail in tones of the sofa color. Remove wall prints.

Update: we’re leaning toward this with a lighter rug