Perhaps a screen with loosely fabricated material, in which the air can still flow through. It will also create interest at the back of your couch.
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does it have a remote, or do you need to use the panel? either way build a box around it attach a screen with hinges and decorate around it. there are some pretty cool DIY ideas on line. "DIY vent covers"

I'd consider a shelf running the length of your sofa at the same height as the bottom of the A/C unit. You can stick something on the shelf in front, like a vase, and move it when the thing is on. Or you could make a gallery wall, with art and one more rectabgle wouldn't be as noticeable.

You could stretch mesh fabric in a dark color like gray or black. You would make it big. To cover most of area over sofa hang low 6-7" above sofa top. You can buy mesh at fabric store. Make a frame that will allow room to cover AC. It should work well.

Treat it like you would any obstacle, if you can't hide it feature it. Add a frame around it, cover the cord to match the wall and smile if anyone mentions it (have a modern art comment ready).