Hey Kimber !! I had the exact opposite problem. My pool was dead square/plum/level but the 4 corners of the patio had different slopes going away from them so the whole thing looked twisted. It did not help one bit that my brain knew it was an illusion, it bothered me daily.
The good news is you will be able to stage furniture, planters, deck boxes, decor, etc to take the eyes off the noticeable areas. It’s trial and error so it may take a few tries to balance something that hides what needs hiding while looking like it belongs in that spot.
I am also of the mind that you paid darn good hard earned money and deserve what you paid for. You’d never accept a brand new Cadillac with a smashed up hood. This is no different but some people don’t want the added time, aggravation and upfront expense of lawyers to fight it. Either fight it or make them reduce the price enough that you will feel great hiding the problem areas.