I would consider built ins on either side but can’t figure out how to do a more modern look. Thank you!

Beautiful room! Those windows are amazing! Can you post a floor plan of the full first floor including dimensions? My question is regarding your furniture placement. If the wall is 23' with the fireplace centred and TV on one side, which side? Will the "empty" wall space be closest or farthest away from your windows? What are you planning for the approximate 9' of space that is not positioned in front of where you hang the TV/face the fire?

I’m not sure yet on the empty space on the right. We are trying to figure that out with a more modern look/feel. The empty wall space in closest to the windows and ideally will be a more elegant sitting area. The TV is on the other side. Here are the floor plans - but ignore the sketch of the built ins/TV. That’s where I’m looking for your advice!

@hhowlett Here is a higher resolution floor plan with a better shot of the space. Much appreciated.

Sorry I am wondering why such a modern FP in what appears to be not at all a modern house with those type of windows. As for the spaces on either side the inspiration one at the top is very simple and just a nice low bench on each side yours will have the TV on the left and then I would say a large piece of art hung lower that the usual 60’ to the center to balance the TV. I guess what I am saying is just do what the first pic shows I am not sure what the 2nd pic shows that interests you

Would open shelving work instead of a traditional built-in?

@norwoodarchitects yes have that on the option list.

I think its a very easy solution. instead of any traditional built ins, have a long low bench with drawers built all the way across from under the fireplaces and then wall to wall just like your inspiration photo. You can then simply hang your TV on the wall at a pleasing level, on the left or right side whichever works with a furniture layout best. You should at this point do a furniture plan layout so you know the best placement. On the other side you can do a picture grouping or floating shelves. I would NOT do 1 big picture. It will compete with the focal point of the fireplace.
A few options would be to do a wall treatments just on that wall. Stone veneer, wood veneer, or just a color accent in paint.
when you do the bench, you want to make the drawers full overlay. This meand no wood from the frame showing around the drawers. Its the clean, simple, look . this way the only thing you'll see is the small crack deliniating each drawer. I would not put a cushion on top, this way you can put some sculptural accessories tall vases etc.

@Patricia Colwell, I was thinking the same thing regarding the windows looking more traditional with the more contemporary style of the fireplace. @Monica Merino Garrido would you say your overall style is traditional or contemporary? I would do as suggested above and plan on a unifying low bench that will run the 23'. If it is not too late, you may want to review the fireplace placement, centred may not be the best option if you don't have any plans for what to place on the other side. Would the overall flow of the space be better suited if you shifted the fireplace /TV area closer to the windows?