You're not explaining how the Sarasvati river evidence, which is radiocarbon dated, does not fully contradict your position.
Do you really believe, in good faith, that the most parsimonious explanation is that a small group of IE-speaking nomads entered India 500+ years after the Sarasvati was drying and population centers had been abandoned, then re-purposed the entire history of the "native" population, wrote themselves completely out of this re-purposing with no memory of where the nomads themselves came from, and then at least hundreds of years after that re-wrote the story of the desiccation of the river (in significantly evolved, non-Rig Vedic Sanskrit) to read as if it was occurring then, ~1000+ years after it actually occurred?
Occam's razor here is clear.
The Rig Vedic speakers were in India when the Sarasvati was a fully flowing river pre-3000 BCE, they documented the drying of the river in later Sanskrit texts, and the Rig Vedic IE corpus was created by at least 3000 BCE based on the radiocarbon dating of the Sarasvati's paleochannel.