I can trace behavioral patterns back 4 generations in my own family. And the only reason I can't go farther is that I have never talked to anyone who knew my great great grandparents. (Which would be difficult given that they were born in the 1800s and died before my birth.)

And even if you don't know what the connection is, that doesn't mean that there isn't one. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127768/ and https://www.bbc.com/future/article/20190326-what-is-epigenet... are examples explaining some of the research on how epigenetics can pass trauma down the generations. We don't know how far it can transmit.

However, regardless of whether there is an impact, EVERY ethnic group has severe trauma in its past. And you generally don't have to go back more than a century or two to find it. The best thing to do is fix our present, and try to create a better future. Which, globally, we've generally been doing at a breathtaking pace.

Albeit with important exceptions. Such as problems that teenage girls began having with mental health starting about 10 years ago. Which may be tied to social media applications.