>>509125389My thoughts exactly.
I knew about the Vandals as there is linguistic evidence of a North/East-Germanic/proto-West-Slavic overlap at some point in late antiquity. There are a bunch words in the Polish language that are derived from Gothic, not West-Germanic.
Also, when they genetically screened certain Iberian islands where the Great Migrations were the last migration wave, instead of typical West-Germanic subclades they instead found an elevation in certain R1a clades generally associated with West-Slavs. Same for Catalonia btw. So that suggests that this came from the Great Migration era, when Goths, Vandals and Alans roamed and settled in those parts.
And of course the linguistic suggestion, correct or not who knows, between what the Vandals called themselves (Lygii/Lugii) and Lech the legendary archfather of the Poles.