It's off topic, but the difference between Iranian farmer and CHG is exceedingly small.
It's just that Eurogenes can't bear the thought that the Indo-Europeans had ancestry which could in any way have the word "Iranian" attached to it.
Of course, imo I think it's now clear that Corded Ware was mostly hunter-gatherer EHG with some added European farmer, and Indo-Europeanized, not really Indo-European, a position which I'm surprised Eurogenes hasn't adopted, because it would get rid of that problem for him.
Its actually possible that Iranian_Neolithic (Transcaucasian after the Mesolithic) entered the PIE gene pool, but in smaller numbers, rather. Concerning CW, there is no other culture as obviously IE as Corded Ware. Not even Yamnaya is that clearly associated with IE speech. The real question for me is, when Corded Ware branched off from Yamnaya.
Version A:
Sredny Stog (PPIE)
Yamnaya (dead) <-> Western steppe (PIE)
Cernavoda (Proto-Anatolian) <-> Corded Ware (LPIE)
Or
Version B:
Sredny Stog (PPIE)
Cernavoda (Proto-Anatolian) <-> Yamnaya-Corded Ware (LPIE)
Yamnaya (Greco-Armenian, Tocharian) <-> Corded Ware (remaining IE)
That's still unresolved. But Sredny Stog itself most likely developed around the Sea of Azow, the Lower Don and Middle Don, probably being associated with the Lower Don culture. Whether it was version A or B, an be resolved by testing Cernavoda and related groups, as well as real early Anatolian speakers. If those are paternally closer to Corded Ware, Yamnaya is unlikely to have been a later branching event and is therefore more likely to be dead, without having left linguistic descendents. If on the other hand Yamnaya is closer to Corded Ware, the opposite is more likely.
Its not definitive that way, but it would be a hint. So far it looks that other Western steppe groups, like Usatovo, are definitely closer to Corded Ware than Yamnaya.
That's the last open question. Going by the uniparentals, the development towards PPIE most likely started at the Lower Don, possibly within the Lower Don culture. But clearly, the important phase was already Sredny Stog.