Subjectively speaking, I think it varies from person to person, because some people learn mathematics better before teaching, while others learn physics better, so teaching students is of course different; Objectively speaking, the school you want to go to is not what you want to teach, but depends on the teachers in that school; Besides, which subject to teach depends on the students in the class, that is, those who have a good foundation in mathematics teach mathematics well, and vice versa. In short, we cannot generalize.