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:

Your sectional and rug are fine but then the effect is ruined by the two dark pieces that don't "belong". Could you possibly change the coffee table for one that is glass and metal? It would really open up your room and give a lighter, friendlier ambiance. Try and get one with two levels so the bottom can be used for storing books, which always give more personality to a room. I would put a light blue and beige pillow on your dark chair to give it some relation to the rug and sofa. The wall behind the chair could be used as a gallery wall or try several fairly large and colorful paintings there. Try a large plant or two against that wall also in some beautiful and interesting pots. Instead of the harsh ceiling light have a table lamp and a table with a lamp on it, one by the chair and one by the sectional. Your room will look so much warmer and user friendly.

Thanks everyone... @Olychick, I was concern the TV would get nothing but glare from the windows with that configuration. The windows are on the west side and receive all the afternoon and evening light., which I like and use.. @decoenthusiate, I agree if I can manage to get a sectional and possibly updated chairs I may be able to use them as the focal point. Or the area rug first and built off it. Budget is around $1000 which is doable utilizing second hand market.... Once I work out the details; the style of pieces and color.... I can purchase items as they become available. Color and style of the pieces are what I am attempting to put together. Here are the dimensions For the sectional, I was considering something basic like this, with a sofa table behind

As per the photo, the lighting seems to be very warm. can you upload more photos of the space and in natural light or may be start with change the lights.