Probably science under a big media veneer of multi-culti spin.
I’m willing to credit DNA analysis as accurate unless you have something more credible to offer.
DNA...Scotland...ping
There were lots of waves of migration into the British Isles. I would guess the Romans brought in a diverse set of genes, both with their armies, and the various traders from various places who followed them.
DNA is Okay, But they weren’t multi-cultural at least prior to 100 years ago. Anyone else from around the world that settled there Assimilated into the scottish culture becasue they HAD to because scottish culture gave them the tools to survive in scotland. The same way european immigrants moved into American and assimilated into the Newly formed English/American culture within a generation or two.
It’s genetic science. Considering how many raid the Berber pirate states made on the coasts of Europe - as fare north as Scotland - in order to seize slaves, these are exactly the genetic finding you’d expect to see.