This. Also, the original speakers of the Indo European languages boiled out of this area. FWIW the modern myths that make them mighty 'Aryan' conquerors do not hold water. Ancient militaries were never good enough for massive occupations. They settled in pasture upland that the agricultural natives did not want. They brought with them the knowledge to breed horses, cattle, and sheep which the locals wanted. And there probably was a bit of cultural glamor attached to them when they arrived. They rode horses! and had a trade network spanning thousands of miles. They were the sort of people you run away from the farm to join.
Shaving appears generally when people get brass weapons that hold a straight edge well enough to make it practical. Beards appear with large scale bathing facilities.