Keep the rectangle. It looks nice. A round table for six is really big and if you try to do any other work on it - like using it as a temporary desk or crafting area, it is hard to "spread out" on a round table. Also, a round table big enough for six makes it hard for guests to reach the serving dishes in the middle.

Is there room behind the sofa to use the console like a sofa table. You could keep some art on the wall , but move the table closer. Although, I don't think it looks crowded. Maybe just pushing things around a bit to tweak the distances and relocating smaller items. Is there room to rotate the dining table so it is parallel with the console?

One more thought, place mats and table runners are much easier to use on a rectangular table.

Nice condo. You have good taste.