No, this paper doesn't seem to talk about regional differences. The implication seems to be that it wouldn't be surprising to find differences between groups that separated more than 2kya, as there was active changes going on before that time. Not that it predicts any specific differences

> If anything they seem to support homogenization of intellectual capacity/mental health in Eurasia since 2kya.

I would be interested in how you came to that conclusion, unless I'm misleading your post and you specifically mean West Eurasia