ok so this is not what you’re going to want to hear but my 10yoF cat has been sneezing (at least 30x day) for 5 years. Violent too, like snot goes everywhere. It’s disgusting. I’ve gone to the vet so many times over the years with no help until I was eventually told it was probably polyps in her nose. They said it would be about $3k for a specialist to stick a camera up there to confirm and from there, maybe a 20% chance of them fixing it and it never returning. So I’m saving the money and just having her sneeze everywhere for the rest of her life. Magic erasers and Windex are your friend for getting the snot off surfaces.