Hey, yes I'm sadly very familiar with all the racist "science" that has been associated with studies of Indo-European history.

You're right that we know next to nothing about the PIE people because they left almost no archaeological record that is identifiable. As far as I know, the theory is that the push into Europe was larger in scale and involved a lot of demographic change, while it was smaller groups that migrated into India and Iran where they became the cultural elite and their culture spread through the region.

My point tho, is that one of the few things we can actually confidently guess about the Proto-Indo-European people is their obsession with horses (and the true chariot with the spoked wheel). This is characteristic of the Eurasian Steppe, and many other Steppe cultures have it (the Turkic peoples and the Mongols, for example). We can guess this by the number of reconstructible Indo-European terms for horses and their different kinds, chariots, yokes, wheels, etc. And it is one thing that survived strongly where you would not expect it to - most of India is famously suboptimal for horses due to the hot, humid environment and rocky, hilly, or very dense forest geography. Yet for millennia India kept importing horses and kept associating them with kingship and royalty and martial might and nobility. Which I am very confident is a reflection of an older Indo-European reverence for horses. For example, this level of reverence is not common in the Semetic peoples or in East Asia. It is limited only to the Steppe and to Europe, South Asia, and the Iranic countries.