10 year old cat with nasal polyp?

I tried multiple vets and hundreds of dollars but nobody seems to have a solution. One vet said it was an upper respiratory infection, they gave him a shot of Convenia and prescribed Clavamox, nothing. Fast forward a couple weeks, he wasn’t eating for an over a day so we took him to another vet that prescribed Cerenia which helped temporarily. They said he could have trouble smelling his food so he wasn’t eating. But it’s still not gone. Xray was clear. Now the vet referred to a specialist that wants over $2000 to anesthetize and do an endoscopy JUST to diagnose. From Jersey, can I drive 3 hours to MD so you can maybe look a him? I’m scared he’s gonna pass away from troubled breathing.

Background:
He lived with my dad who recently passed and I took him in. In the last year I noticed he has had difficulty breathing but some days it sounds clear, most days it’s worse. It sounds like something is restricting his airway.

He does sneeze often and when he does it’s usually 15+ sneezes in a row like he’s trying to get something out. Last night I counted 21 sneezes in a row. He also sometimes sounds like he’s choking or trying to spit something out but nothing comes out. He does have greenish/yellow boogers once every couple of weeks and also has discharge from his eye.

I know it’s the holidays but I’ll do anything for a chance to help my little guy that reminds me of my father everyday. *Update, just made an appt for 12/30 at 11:30am!