You will probably get more help if you post this in "design dilemma" or "home decorating" thread, not windows :)

Send the curtains back. Do you need curtains for privacy.? I would do roller shades on the door, the same color as the door so you don't see them up or down. For the window: you need a thicker rod hung wider than the window so when panels are open they stack off the glass. Also the rod should be hung 2/3 of the way up from the window trim, closer to the crown molding & the panels should just touch the floor. Get panels either the color of the trim or the wall. You are right the white is too bright. The rug & sectional work well. Coffee table should be round, maybe glass to show off some of the rug. I don't think the navy is a good accent color in your room.

Consider a privacy film for the door-the curtains take away from the pretty doors. I agree that the curtains are too stark. They're also too short and not full enough. If the curtains are 84", try 96" instead. Try to find something closer to the wall color. The gray, white and navy are a bit blah. Is there a color you like that you can add in with different pillows and a throw as suggested? I also agree that the coffee table is not quite right. I'd consider a round ottoman, maybe in leather, that you can add a tray to for drinks and a bit of decor. What is the distance inside the U shape? You could add a pretty demilune shaped table next to the door to ground the artwork. Maybe something like this with just a small lamp and pretty bowl.

https://www.hayneedle.com/product/belham-living-james-half-round-mid-century-modern-sofa-table.cfm

For the coffee table, try an ottoman or round coffee table. It will work a lot better than the one you currently have. See the design we have posted below for an idea of what the coffee table/ottoman might look like, as well as ideas for rugs. You might also look into adding betting lighting via lamps.

A Little Aloha: Living Room · More Info

Whimsical Farmhouse: Family Room · More Info

I do like the color better. How wide is your window?

HI -- Have wood blinds to the door wood color for the doors and the window . Then have full height drape side panels with two panels each side ( you need 4 panels ) hung at the sides of the window as wide as you can . Back tab or grommet headers on a full length rod . Make sure the drape panels stay at the sides of the window . This will make the window seem much wider . You will then not need those decor items on the wall . This will be a more finished look . Find panels that have a texture or a tone on tone pattern . Bed Bath and Beyond has great drapes and fixtures .