It depends on how you look at things. The Nordic Bronze age spread around the entire Baltic as well, and genetic markers associated with Finnic cultures appeared much later, and in areas further north and east.

However, as the article mentions, it's unwise to assume there is a 100% correlation between genetic markers and culture/language. The Baltic Sea region has been a trade hub since before the the first indo-european migrations into the area, and some genetic mixing must have been unavoidable.

You’re comment about not assuming a correlation of language and genetics is spot on for this topic. In the linked article (or maybe it was another article on this topic) they mention that genetic research shows that Etruscans shared much of the same step-derived ancestry as the Latin speaking Italians. It appears that, when then step invaders came in, at least one group of them picked up a local non-IE language even while their genetics overcame the original speakers.