Great, thanks! I would use a round table that can extend to oval when you have company in the dining area, right over near the kitchen. One chair backing into the corner, rather than a chair with its back to the kitchen door. The desk can stay right where you have it in this photo. Sofa on the wall with the windows with a side table at each end. Two chairs across from it with a table between them. I sketched a pic but can't post comments on my phone, boo :(

If the storage is being used and also enjoyed as a seat, I would leave it. Float your sofa in the room, perpendicular to the short wall between the kitchen door and that little nook. In the nook, create a little seating area. You could slide a desk into it if you enjoy sitting at a table to write or use your devices; add a floor-to-ceiling bookshelf and position a chair in front of it; run an 18" counter top along the back wall and add two swivel stools; tuck a daybed in there...With a great piece of art and some lighting from a table lamp, hanging pendant(s), or floor lamp it will be a cozy corner for one or two people :)

If it was just my husband and I it would be fine the way it is. with children it’s a huge safety issue because if they stand on the couch they can go down the stairs. It’s driving me crazy to say the least. I feel others might look at the room differently than I would and would have a better idea

IMO a cat litter box never belongs in a space where there is a dining table so put that in the office to start.