Leave the arches un covered and hang the drapes at the top of the windows on both styles and use the same material on both

You could install a rod over the top of those arched windows, but just have drapery panels flanking each one (so the arch is not covered up). Make the rod height the same on both arched windows, but lower it a bit on the window by the table. It's okay if they don't all have the exact same height. Use the same fabric or a coordinate so they relate to each other. Same drapery hardware on all.