Chair...

Make adjustments with the piano first. It should angle across a corner and the lid should open like a jewel box to throw the sound out into the room, not up against a wall or windows. You have a lot of hard surfaces, so consider a rug for under the piano and perhaps some stationary panels to lie against the walls at each end of the curved windows. In addition, I don't believe anyone on the sofas can reach the coffee table to put down a drink or other item. 12-18" from the sofas is ideal. Is the blue rug wide enough to turn the other way so the sofas sit entirely on it (leaving room for another rug under the piano.)

I like what you’ve chosen but I also think you should invest in quite a few huge glossy green plants and even trees for the curved window, to make it look like a fantastc conservatory and also to bring out the green of the sofas.

I also think it mght be nice to layer another rug on top of the one you have. You could even do an oversized cowhide, but then I think you need a lot of blue leather/faux fur pillows on the green sofa

22"x22" Animal Fur Print Blue Faux Leather Throw Pillow Cover - Blue Fluff · More Info

Blue 20"x20" Pillow Cover, Leather, Patchwork, Sky Half Tone · More Info

You clearly like blue. Feels like the wrong wall color here........sorry. In fact, The wood trim feels like it is simply taking over. A lovely view, obscured by the "Heavy" of wood, and the flooring isn't a complement to that dark tone either.

I realize not what you asked. But If you love the blue? It's crying for a wood trim paint job. Again, sorry, just what I see. Rug is far too small : ) and cocktail table is not working. Too rustic, too small. Larger and a stone or marble top? Yes.

LOVE your room design, the wood, the shape. I think the floor and dark window frames with the caramel insets are all grand together. The view is fabulous--but what happens at night with all the black the windows would be? The caramel chair is perfect but the ottomans chosen don't work. Too large and poufy with that chair. Keep looking for a side table that does the chair and piano justice. I see a lot of hard surfaces, glass&metal tables, no curtains, thin area rug what happens when the piano is being played? Acoustically I bet the room is not working.

Thanks for all the suggestions. The colors may be a little off in the photo because there's no blue in the room, it's grey. I know the wood tones aren't what's in style now, but it's not even in the realm of our budget to change - there is a LOT of woodwork throughout this (custom) house. The rug is 9x13 - perhaps scale is hard to see - it's a large room. Maybe the piano needs to go back. :)

You’ll need to post more photos and a plan that shows scale. The piano just needs to be shifted and that is step one of many to get this room right for you.

Thanks for the suggestion on plants above!

Fwiw - here are pro photos from a few years ago (staged) that show two views of the room.

I think your room is beautiful and I love all the wood. Keep the piano!! While I really like the leather chair, I think the color of the grey one works better in your space. It brings the color of the rug into that part of the room, while the caramel chair kind of blends into the wood and adds more of that same color.
I would do a gray chair with matching ottoman, or if you can find a gray and green print...that would be pretty fabulous! Green plants will also complement the gorgeous sofas and bring more of that color into the room. Even though you're getting lots of comments on things you didn't ask which I normally try to resist, I'm going to do it, too. I really think the coffee table isn't working. If you look at the staged photos and how large the table is between the parallel sofas, I think something larger would work better. And I agree with the comment that perhaps a stone table would work really well with your room and colors...the stripey wood just seems too rustic for the rest of the room.
Another thing that works so well in the staged room is that the rug relates so well to the sofas. To me, the rug you're using doesn't really show off the green sofas to their best advantage. A rug that incorporates the green would work better, I think.

I rotated the piano a little and agree. Thanks!

 I love your windows they drew me to your dilemma I think the leather chair will look Grand and the pouf ottoman in the in the same color if you can of the chair but I don't think your room cost for a hide with your other furnishings