Let me ask what you hope to gain by doing window seats here? I find that most of the time they are rarely used. That said they can create added interior storage if needed and can add a certain amount of charm when done up with cushions and pillows. In your case you would just stop them where the window casing ends. The sides would be finished on each end.

I agree with Design Interior South. The window seats look great in photos but NO ONE wants to sit on them. Adding them will be $$$ and the pay back is nothing.

You could try just placing ottomans there and see if anyone uses them..

Lucky you! You have a beautiful view out your windows. I think the swivel chairs give you great access to that view. I would remove the lamps and maybe put in recessed lighting or add sconces above the fireplace. No window seats necessary.

I too would forget window seating,for the reasons cited by all current advisors.
You could consider filling the spaces either side of the fireplace with low bookshelves painted to match other trim.
They would give a spot for boxed games,books,mags,atlases etc and a larger area to put lamps along the top.

No window seats they will truly do nothing for seating . Move all the furniture back to open the center of the space

it looks like they each would overlap with a door or window on one side? I think that would be awkward - I’d skip them like the advice above

Agree with benches or ottomans that can be easily moved for additional seating. Whatever you decide, the tiny lamps and tables distract from your beautiful space.

Agree, no windowseats built in. Bookcase shelving or ottomans.

A lovely solution that would really complement your room (imagine with your windows). Plant would just be on the left side, given the sliding door.

No shelving or built in there if you have a pet put their pet bed there or you could put a small big debt table and chairs there if you would like to maybe play chest or sit there by the window and maybe one other end of the room and the the opposite side you can maybe put a lounging bench that you would like to Lounge in

If you like plants you could even put a tall tree plant there that would be very nice