Hello. I do not claim to know their purpose but can guess.
Islam appears to have the purpose to create a world united under Islam. Islam says there is a day of judgment where each person will be judged on each atom's weight of their good & bad deeds.
Hinduism appears similar to Judaism, which appears why India loves Israel. Hinduism appears to exist for the tribal supremacy of the Brahmin caste and those who fund the Brahmin caste.