My read of it was that there was a Jomon culture that was superseded by the Yamato culture. The Yamato culture was mostly from people coming from what is now Ko

My read of it was that there was a Jomon culture that was superseded by the Yamato culture. The Yamato culture was mostly from people coming from what is now Korea but there probably was admixture with the people already there. But this peopling was a good 2000+ years ago. So it’s a bit like saying my ancestors were here 13000 years ago and most of yours were here only 2000 years ago. Furthermore, we have no idea how many waves of people have migrated to those islands.