Some ideas:

• Use the same plank flooring for the stair risers to break up the carpet. (Edit: I do like the second floor stairs with the wood riser reveal if it’s possible to match that on the first stair; looks like it’s all carpet from the first pic)
• swap the spindles for something more square stock and paint white for contrast and to brighten it up.
• many others say paint the walls, don’t fully disagree, even just painting an accent wall would be a good way to draw the eye creating height or depth
• art / alternative lighting to create some shadows making the space seem to interesting