You have ‘people’ linked when they are 20+thousand years apart, and say that they are linked. Not by lineage but by inference of artistic styles when there is no connection between them, so artistic styles cannot be considered, no matter how you may present such.
How many connections were we completely in the dark on before DNA Testing became available?
Languages, customs, not big customs like fire and clothing, but the ability to create and use a needle, or to create beads with very small apertures . . .
Some things stand out a bit more.
But I have to get reading!!
Mind is the rider.