Do you not see the irony in trying to prove a Andronovo steppe horse and chariot model expansion; the first god of the first sentence is connected with oceans, not steppe. Now why would a bunch of R1a Z93 conquering elite speaking Indo-European language bother mixing ocean gods with the horse and chariot? Remember they buried their dead with chariots and horses in kurgans, why would they not mention that? Did they have a Varuṇa in Andronovo or Kurgan Ukraine or Tocharians? There is a somewhat similar Aruna in Hittite mythology if you are curious.
I don't see any irony in the idea that an Indo-European God who used to be a Sky God associated with rain later becoming associated with the ocean, and I don't see what that has to do with Goga's theories about the Zagros Mountains. Here's what Encyclopedia Mythica has to say about Varuna:
"Though he only has about a dozen hymns addressed to him in the
Rig Veda, Varuna seems to be one of the most important of the Vedic gods. In pre-Vedic times, he was the supreme lord of the cosmos, the keeper of divine order, the bringer of rain, the enforcer of contracts. He is called omnipotent and omniscient; he is responsible for the sun to move in the sky, for day and night to stay separate, and for the earth to keep its form; he watches the flight of every bird, is present at every gathering, and knows every thought. His name means "he who covers", and this probably refers to the sky. Varuna is the keeper of the cosmic order, a force called
rta. It is
rta which keeps everything working as it should, and Varuna's role as the one who governs rta makes him very important indeed. He is very closely linked to the god
Mitra. Varuna is one of the
Adityas and considered to be an
asura, when those beings were still god-like and had not yet degenerated into demons. He is also associated with the moon and
Soma, in Soma's incarnation as the drink of the gods. Varuna is seen as a white man in golden armor riding a
Makara (a sea monster), holding a noose or lasso made from a snake. Varuna is the keeper of the celestial waters, those which flow from the openings in the sky in the form of rain. He was worshiped with veneration and a healthy amount of fear, for as an asura Varuna did have his sinister aspects and was known to punish mortals who did not keep their word. He was the cosmic hangman and his usual method of punishment was to capture the offender with his noose. He was also a lord of the dead, a position he shared with Yama, and could confer immortality if he so chose.
In Vedic times, the worship of Varuna fell off as he was supplanted by
Indra as king of the gods. One possible reason for this may go back to Indra's most famous exploit. When
Vritra stole all the waters of the universe, the waters which Varuna was in charge of, it was Indra who had to fight the demon and get them back. It may have been because of this that Indra was able to supplant the overlordship of Varuna and become lord of the gods himself. Varuna then became god of the oceans and rivers; still important, but with hardly the grandeur he once had. The souls of those who drowned went to him, and he was attended by the nagas.Varuna faded away with the ascendancy of
Shiva and
Vishnu. His lofty position may have lived on, however, for he may be the same as the Zoroastrian supreme god
Ahura Mazda."
Although I'm dubious about quoting Wikipedia unless it leads me back to some other source, here's what it has to say about the Hittite God Aruna. Note the reference to the Black Sea.
"Various origins of this name are proposed. It was highy possible that it has a same origin as the name of the
Vedic god
Varuna. It could also be a reconstruction of the
Indo-European mori or Greek words for
Black Sea, μόρυχος. A
Hattic origin through the place name
Arianna has also been suggested. A connection with Indo-European er-, or- (‘stir, move’), and thus the Hittite name is believed to have a same origin as
Sanskrit arṇava ."