We are simply seeking connection, and that is why spirituality has to be personal, handcrafted and revisited when some aspects feel outgrown or irrelevant.
A belief in the existence of God does not mean that you believe in any particular religion. A person can believe in God but still abstain from religion.
We can find the Dark Mother in Goddess-worshiping traditions. Kali, Hindu Goddess of creation, destruction and shadow, is often depicted with dark skin.
Tantra is Hinduism’s rebellious branch. Only later was it appropriated by other Eastern religions, and is usually presented in this updated way to the West.