Part I of the Divine Code explains the fundamentals or principles of faith, but it doesn't give their exact number. In fact, there are no exact numbers. Rambam's list is one of many. For example, Rabbi Joseph Albo wrote that there are three fundamental principles: existence of G-d, revelation, and reward and punishment.
https://www.sefaria.org/Sefer_HaIkkarim%2C_Maamar_1.26.1?lang=bi&with=all&lang2=en I don't think Albo lost his share in the World to Come just because he disagreed with Maimonides.