Except there is no such lack of evidence. Just the opposite. The amber trade with the Baltic is well established to everywhere in Europe (even far flung islands like Ireland), as far back in antiquity as we see Homo Sapiens living in Europe.
That doesn’t mean it didn’t just get there because someone traveled, all apart from ‘trade’ - or that the material didn’t simply fall there, too, and this is all that’s been found of it.