That train of thought makes a lot of sense! I do have some other questions. For example, what points you to the region between Herzegovina and Kosovo as the homeland of the lineage? Or, like you said later, southwest Serbia and Kosovo in the middle ages?
I’ve seen that calculators do point to Kosovo as the place of origin for J-PH502, but what is the basis for that? And the other regions you mentioned, of course.
Speaking of this common Vlach origin, and I hope it’s not an issue to stray off topic a little, but what are some other, possibly major? lineages in the modern Albanian ethnos that can be attributed to the Vlachs? Considering that both come from Illyrians, Thracians, and whatever else existed in between, how do you determine what comes from romanised Paleo-Balkan people and what comes from Proto-Albanians?