You need coffee tables in both spaces. I'd go for glass top tables with metal legs since the upholstered pieces are visually dense.

I don’t know your rug budget, so these are just ideas. I love this first one for it’s very cool-retro 80’s contempo vibe. And brown is coming back in a big way, your sofa was a great choice. https://www.cb2.com/hogan-handknotted-mocha-viscose-rug/f22504 I love this one because of the design and colors: https://www.cb2.com/eros-hand-knotted-brown-rug/f25598

I would say that in general carpet is an unpopular floor surface for the first floor. I like it in bedrooms, and it is used more frequently upstairs (if you have a two story house) and in bedrooms. The drawback to it is that it shows traffic patterns more readily than either wood or LVP. That being said, some people definitely like it in their family rooms, so if that is really what you prefer, it's your money and your house, you should please yourself. If you're concerned about getting an area rug in a standard size and having it work in your space, keep in mind that carpet retailers can cut remnants to a custom size and bind the edges to make an area rug, and in fact can do that with any of their stock or special order carpet. I did that in my living room and I have a 9 X 12. So I could have gotten a standard size but a custom order pattern was closer to what I wanted. And it didn't cost any more than a standard rug. More than the cheap polyester ones, but not as much as an expensive wool one (it's nylon). It is not bedroom plush. There is a lot of variety available if you have a large retailer near you.

I think it will be just fine. As others have mentioned, it may initially feel a little empty because you're used to having such a large piece there. But even with 2 story rooms, it's ok to not to decorate all the way to the ceiling. One suggestion though: consider bringing your seating are a little closer together centered on the fireplace. Right now the sofa and the chair look really far from eachother and the sofa looks a bit far from the TV too and not even touching the rug. It's ok to have furniture floating together in the room. You can also add more volume by putting a console table behind the couch.