The Iranian mythology is not specific about where they originally came from (just that it was a cold place). The Avesta talks about various land including the Punjab. Western Iran remains unknown. Recorded history for Iran starts at 900 BCE, not before (does not mean there were no Iranians there before, just that there is no evidence for that). There is no archaeological evidence whatsoever to suggest "Aryans" came from Siberia or elsewhere. There is equally no evidence that they originated in India. Random dates don't work, the AIT requires a specific series of events happening at specific times. That has run into problems especially over a river called Sarasvati. All we have are conjectures, no evidence. a linguistic connection exists, nothing else does.