I think a lot of people can relate to this design struggle! In our old apartment, Joey and I had an awkward wall air conditioning unit. I pinned a vintage silk scarf over it! This way, the scarf could be gathered up on top while the AC was on, but otherwise covered it up with something much prettier!
Whenever there is an eyesore in a room that can’t be moved, I try to distract from it. Place a larger piece of art over your couch, add some curtains to the windows, just make sure there are other things going on on the walls.