There were almost pure WHG still living in Eastern Europe (in and around modern day Belarus) during the Bronze Age. And the Kurgan cultures of the region that came after Corded Ware had very high levels of WHG admix, plus Balto-Slavic clades of R1a.
The last Jones paper didn't get into this, but the next one on the Baltic will. So Baltic and East Central Europe is no longer much of a mystery.
I don't know what the story is yet with Northwestern Europe or the Finnic and former Finnic parts of Northeastern Europe.