You can look at the ICD code written by the doctor on the first page of the inpatient medical record. If it starts with q, it is a real congenital disease. In addition, in ICD 10, deviated nasal septum is not a congenital disease. After all, it's not all congenital diseases.
About the insurance company calling you a pre-insurance disease, how do you describe this symptom in your medical record? Have you ever been diagnosed? Is this symptom necessarily a manifestation of nasal septum deviation? Is it possible that rhinitis or other diseases are also such symptoms? If there is no necessary connection, you can't say that your nasal septum deviation is a preventive disease.
Regarding the issue of notification before insurance (Article 17 of the Insurance Law), if you want them to pay compensation, it depends on the local judicial environment. How did the court deal with most of this piece? Did your mother sign any clauses in the contract that need to be informed? If you have signed it, you will be diagnosed before the insurance. I don't think you can compensate even if you go to court.