The Portuguese and Galicians claim to be and look Celtic have haplogroup R-DF27...
They also brought a Celtic language and culture that we know of from archeology. Paloegenomics show that during that same time the percentage of ancestry from Central Europe rose all over the Iberian Peninsula.
That can only mean that branches of DF27 were like a satellite population of the Gauls, living in what we know today as southern France.
They adopted their culture and language , and then joined the rest of the Hispanics in Iberia later during the Iron Age.
There's no other explanation possible. So we should conclude that R1b-DF27 wasn't born in Iberia as the scientific consensus claims, it should have appeared in France.