Love the simple colored bench (preferably in the same color palette as the room) and the triangle accent wall. Love the raw hanging lightbulb element. Would potentially add a fuzzy rug and some more nature elements.
So ignore everything but the white and yellow line! What if we did that but in white and baby blue on the gray wall behind the toys? Maybe do it on a bit steeper of an angle so that the color stretches further across the wall?