Based on YFull date estimates, the lineages below E-Z5018 appear to have experienced major diversification events in 1800 BC and again in 1200 BC.
At the beginning of this period FGC11457 appears to have entered a 600 year long bottle neck in the Balkans. Then in 1200 BC the MRCA founded a succession of lineages stretching from the Balkans to Poland and Scandinavia.
Using YFull sample data, Y84587 appears to have gone straight to Scandinavia while FGC11450 appears to have diversified in Poland before reaching Scandinavia.
What was happening between Germany, Poland and Scandinavia in 1200 BC?
The most unprecedented battle of Bronze Age northern Europe, The Tollense River Battle.
"About 3200 years ago, two armies clashed at a river crossing near the Baltic Sea. The confrontation can’t be found in any history books—the written word didn’t become common in these parts for another 2000 years—but this was no skirmish between local clans. Thousands of warriors came together in a brutal struggle, perhaps fought on a single day, using weapons crafted from wood, flint, and bronze, a metal that was then the height of military technology. "
"At the time of the battle, northern Europe seems to have been devoid of towns or even small villages. As far as archaeologists can tell, people here were loosely connected culturally to Scandinavia and lived with their extended families on individual farmsteads, with a population density of fewer than five people per square kilometer."
"And yet chemical tracers in the remains suggest that most of the Tollense warriors came from hundreds of kilometers away."
"DNA from teeth suggests some warriors are related to modern southern Europeans and others to people living in modern-day Poland and Scandinavia. "
The subclades of E-FGC11457 have very little presence or diversity in Germany. If they were among the warriors fighting at the Tollense River, could their loss in this battle have prevented them from diversifying in Germany? Or did their victory secure their passage north to a pacified Scandinavia?
What does seem clear is that these lineages did somehow become established in Scandinavia no earlier than 1200 BC. The presence of Scandinavian Z38485 in Scotland could then have been a Viking Age newcomer.
It will be interesting to see what Y-DNA is found in Tollense and how the tree on YFull develops.