The Beaker People antedate the Picts. It’s weird, the British Isles were a big destination for mass migrations, and in historical times, for invasion, right up until the late 17th c (subsequent attempts have failed).
That history is pretty sparsely understood though, am I correct in that?
I plan someday to read about the Picts. Those people made the most beautiful artworks in stone and metal, just lovely.