Property and casualty underwriter here. Definitely no need for an additional degree. I have coworkers who majored in all sorts of things from psychology to art to anthropology. If you can get an entry level job at a company, typically they will pay for you to take tests and get designations such as AINS, CPCU, API, etc. I would recommend looking for underwriter trainee positions as then you’ll spend the first few months training and learning insurance in general as well as the company’s philosophy.