Both of those studies are kind of outdated, I'm not saying they're not legit (Although some people seem to question Nasidze's paper), I'm just saying that sometimes, when a certain lineage is not that common in an area yet out of nowhere shows up in significant numbers, it usually indicates a genetic drift.
It's possible that R2a was carried by ancient Iranians, but it's also equally possible that it was carried by ancient Dravidians too, my point is, the lineage belongs to different groups, as of today the highest people that carry this lineage actually live in Eastern India, and they're both Indo-Aryans and Dravidians, it also exists among both caste and tribal groups, meaning this lineage predates all this caste/tribal + Aryan/Dravidian stuff, R1a1a too has a similar history in South Asia which is contrary to the belief that it's supposed to be the Aryan lineage or what not.
One thing for sure, R1a1a and R2a correlate only in South Asia, Middle East, and Central Asia, but not in Europe, meaning if R1a1a was part or the early Indo-Europeans, R2a clearly was not.
Maybe, maybe not, but when it comes to facts there's no maybe, generally speaking, the story with R2a is not very clear because it's not a very popular lineage in Europe which means not much has been studied on it, but I imagine the story would be similar to the R1b relationship between Europe and the Middle East.
Again, R2a belongs to different groups, but since we're talking about Dravidians, the most leading theory is that they're the original population that lived in the Indus valley before migrating to South India, prior to that their ancestors were probably a mix of Neolithic migrants from the Middle East and local native Asians.
You misunderstood what this person was saying, there was no R2a found, he/she was simply taking current R2a STR values from FTDNA projects and calculating the TMRCA based on these STR values, which eventually according to his/her theory, it dates back to that time period, this is a person's opinion, not evidence.