According to Chazal, the original human was both male and female.
Vayikra Rabba 14:1 et al:
??? ?’ ????? ?? ????: ???? ???? ????? ???? ??? ??? ?????? ?????????? ????. ??? ??? ????: ???? ????? ?? ??????? ???? ????? ????? ???? ???? ?? ???? ?? ?????. ??????? ???: ???? ??? ????????! ??? ???: ???????, ??????: ????? ?????.
R. Shmuel bar Nachman said: When God created Adam, he created him androgynous. Reish Lakish elaborated: At the time [Adam] was created, two faces were created. Then they were split and two backs were made; a back for the male and a back for the female.
He answered: [Therefore what the Midrash said stands, because she was originally one side of the entire human; Hashem simply cut her side off and made them two separate persons.]
Accordingly, answers like ‘to help man’ only explain why the woman was split from the man (and that is where the Torah says it). They do not explain the purpose of her essence, which was created together with the man’s.