Trinity Or the Pagan Beliefs???

Every now and than, we here Christians going berserk over Trinitarian beliefs and try their best to present in a classic way, that look like some kinda true, but not almost true.

If we ever go through the pages of History, we can see that
Sumerian used to believe in their own Version of Trinity i.e.Annu + Anlil + Aya or Aiyah, the Egyptians believed in the Trinitarian Version of Ozirus + Isis + Horus, while the Hindus also believed in the Trinity of Indra + Mithra + Vayo or Vayuv.

Now since the so-called Christians have enough ammo, they must waste it on checking the authenticity of Sumerians, Egyptians and Hindus’ beliefs by turning the pages of History. They should also check if they are really following pagan based Christian beliefs and who incorporated them into Christianity

I don't know enough about those other religions to comment, but I do know enough about ancient Egyptian believes to say that your claim is definitely not true. Osiris and Isis were according to the myths husband and wife and Horus was their son. There is nothing trinitarian about them. Osiris had a brother named Seth, so that would make it a quartet instead of a trinity? Then there's geb (earth) and nut (sky), the parents of the two brothers.

It's actually common in polytheisms for multiple Gods to be related to one another. Just think of the Greek god Zeus, the son of Cronus and Rhea, married to Hera, father of Aphrodite by Dione. But also father to Athena, Apollo and Artemis, Hermes, Persephone by Demeter, Dionysus, Perseus, Heracles, Helen, Minos, and the Muses by Mnemosyne; and finally father to Ares, Hebe and Hephaestus by Hera.

A quick search on the alleged trinity of hinduism showed that it is a false claim to. Where Indra and vayu are indeed hindu gods, mithra is a zoroastrian god, and they were worshipped side to side at a certain time as part of a peace treaty, but that was in a set of 5 gods, not 3! According to wikipedia:
The first extant record of Mitra/Mithra is in the inscribed peace treaty between Hittites and the Hurrian kingdom of the Mitanni in the area southeast of Lake Van, c. 1400 BCE. There Mitra/Mithra appears in the company of Varuna, Indra and the twin horsemen (Ashwini Twins), the Nasatyas, as the five beings invoked as witnesses and keepers of the pact, and all of whom the rulers of the Mitanni apparently worshipped. (Campbell, 1964 p 256).

I did a quick search for the third alleged trinity but I didn't find information on any of those three names. But with two of the three claims already scrutinized I don't see much point in taking this any further.