The Sumerian account of creation differs from teh Australian aboriginal.
Sumerian: According to the Sumerian story “Enki and Ninmah,” the lesser gods, burdened with the toil of creating the earth, complained to Namma, the primeval mother, about their hard work. She in turn roused her son Enki, the god of wisdom, and urged him to create a substitute to free the gods from their toil.
Australian aborigine: The Aboriginals believed that the entire world was made by their Ancestors way back in the very beginning of time, the Dreamtime.
I don’t see this related to other creation myths - especially the Indo-European one.
You only share a small part of the full stories and bigger picture.
And for both where did their gods originate from? Look into the Wandjina creation myths of the Aborigines and compare them with the Sumerian. And the creation myths of many Native Americans, some African tribes such as the Dogon, the Hindu, and many others.