Hi, There’s so much you can do like:
here are a ton of pictures for inspiration.
Well light colours make spaces seem open because they reflect light while dark colours absorb light. Painting your entire room a dark colour will make it seem smaller - you could just paint one wall. Keep the walls opposite the window and balcony light. Go for a colour you like. Navy blue goes well with white furniture.
I also found a plum/purple colour…looks awesome!
Or have dark decor…