Hittite and proto-Iranians came from the same early PIEan source SOUTH of Caucasus. Not Yamnaya.
Graeco-Aryans = Hittites & Iranians = came from 1 source. Both linked to Y-DNA J2a, R1b, R2a and T & L.
Some minor Steppes ancestry in Kurds is from the Scythians and Parthians : https://www.theapricity.com/forum/sh...ight=scythians