According to enter_tain/Dardapara/fake Gashi gurit E-V13 was a minority Y-DNA in Western Balkans, and that's all the story, during Roman times they grew up in size and populated all Balkans.
The problem is that the modern data contradicts any such claims 100 %. E-V13 did grow more in the EBA than in the Roman era! And it grew many dozens of times more in the LBA-EIA transition than in the Roman era. This means if its not being found in the Balkans, over large territories, by the Bronze Age, it simply wasn't there, at least not in the inhumation burial groups. And this inevitably links them with the Carpatho-Balkan cremating groups, in the Transitional Period to Eastern Urnfield/Channelled Ware/Thracians.
In the Roman period, after the Dacians being conquered, there was a near collapse and great loss of many E-V13 lineages. Nothing like a significant growth at all, but the very opposite. It is in the modern data and distribution, and unlikey other such models, its not questionable or ambiguous, but 100 percent clear.
Because new branches could be wrongly dated by some 100 years, single ones in particular, but the whole phylogeny of E-V13 can't be so completely wrong, we already have the data to prove it. There was absolutely no significant growth in the Roman period, E-V13 was drastically shrinking, with many lineages getting lost, in the Roman era. They grew more with Celts and Dacians than with Romans.
Also look at the Urnfield peak of E-V13:
At that time J-L283 was already in control of much of the Balkans. Its very clear that such a large haplogroup for the Carpatho-Balkan region can't hide in between J-L283 settled areas of Eastern Bosnia, which is the only non-Thracian, Carpathian-related region not sampled yet. Also note the later Iron Age Illyrian expanson, especially of the Albanian-related J-L283 lineages. They expanded after Urnfield, within the Hallstatt Iron Age. Then came the Celts.
The Roman era was for E-V13 the worst period since the invasion of the Tumulus culture from the West (Koszider horizon, collapse of various Pannnonian Tell cultures).