I love the clean, uncluttered look of your home and you've made some great furniture choices. My first thought, though, is that I would try to rework the sofa/sectional placement. It really is unwelcoming looking to me to have the back where it is facing a wall, when it could be oriented to look into the room and out the windows. It seems like if it were placed in the corner under the stairs that it would feel open and invite you to come in and sit. I'd hate to be cooking in the kitchen and have the family or guests with their backs to me. If you are having a TV in another room close by, do you need one in that room, too? If, so placing a 70" unit will probably only work as you have it. But, to me, it's not going to look like a living room but more like a movie theater, which is fine if that's what you're going for. It seems like it won't be a cozy conversation area, though. I might actually flip the rooms and put the dining room where you have the sofa now. I was looking at lights used with dining rooms and ghost chairs and saw this, maybe would work in the living room? Kind of fun. don't know if it would look as good without the colored walls though. And I thought something like these were interesting to consider for over your table:

Be careful not to go overboard using different neutrals. Some neutrals are warm toned, some are cool toned. You can combine warm and cool in a space but it is hard to pull off. If you aren’t confident in your decorating skills, pick one neutral tone and stick with it. Then add interest with accent colors. A good place to start is to find a properly sized fabulous rug with colors that work with your floors and walls. Then build the rest of your choices from the rug style and colors.

Curtains would be a good idea. Even though you have blinds for privacy, curtains make the windows look finished. A little eyeliner besides the mascara. I would not do a colored curtain here. Curtains are just to darn expensive to have to switch out when your color palette changes. I would suggest white or off white, whichever you prefer in a silk or silk-like fabric, and get a marvelous trim for the edge. The edge trim can be in a white and black or whatever color you want to take from your rug or elsewhere in the room. I would not do a curtain trim in gold here because I see 4 windows, for 8 panels, that would be a lot of gold. You want tasteful gold embellishment in a space, not Liberace in Las Vegas. Here are some examples of trimmed curtains. Buy the plain curtain, and then buy the trim of your choice, and buy extra trim to embellish throw pillows, and buy coordinating different scale trim for other throw pillows. Another curtain option is a white curtain with a subtle pattern woven or printed on it.

I have replaced the harp with a shorter one I had around the house and am using a finial from a lamp I'm currently not using. Not big changes and probably not very noticeable in this picture, however. So, for my "investment" of $42, I think it looks fine.....................for now. (I hesitated to post a picture because you can hardly see the finial or the difference in the height of the shade, but here it is anyway.)