IMO solar shades to control the light and heat they give privacy during the day and allow you to keep the view and drapes at night for privacy . As for your dilemma now no one expects all the windows in a house to look exactly the same outside you are worrying over nothing IMO

WOw...@patricia colwell "consulting". That is not consulting; that is unnecessary judgment and bashing. I'm actually shocked that you're considered a "pro." @ Grey Owl. I love your nook; it's very sweet. You can totally add little shelving on the opposite side of the existing window to create your Cozy Book Nook. I'm so sorry you have not received more professional guidance here.

If the windows had been treated as one when they were being trimmed out, without drywall in between them (and beefier trim all around!), you’d have a much easier time deciding on a window treatment. Fortunately, this can easily be done now: Now you have ONE (double) window that can be treated as such! You could also make it a “triple” window:

Looking at your setup from that second angle suggests you’d have proper clearance on the left but now I wonder about the right side The space on the right is limited by the protruding fireplace “trim” (the mini “hood” above the fireplace opening and the detail below the opening). To see what might work you could purchase a 96” or 104” drapery panel, (whatever appropriate length) hold it up at height rod would be, and see if it hangs ok. Does it look squished, left to right by the fireplace? Does it hang freely? A heavier fabric panel will take up more soace, especially if it’s lined. Maybe a cotton canvas but no lining, or a blackout panel would fit. To help you decide about adequate space, consider the function of the slider. Do you open it a lot? Is that outdoor space a spot you use all the time, or does the door stay primarily closed and youre not going theough that door much. The right panel could hang partially over the door handle (door seldom opened) or it could hang so it fuly clears the door handle (use door all the time). Alternatively, you could mount a shade over the arched window that is long enogh to cover the sliders when shade is let down. (Prob requires a custom made at this length). Whether a shade or drapery, the slider door handle and limited width and height of space will inform your decision as Im sure you already know. Either woud work, but neither are ”perfect”. But perfect is seldom needed. The pros have great advice; maybe they‘ll weigh in