Yeah this is indeed interesting, cause your haplogroup is just R, that means you are a living Mal'ta boy lol. Although you said it is the wrong group but still what's your mt haplogroup?
K1b1b - per 23&me Ancient Irish/Welsh/Scot/Brit - maybe pre-Celtic, maybe indigenous. They may have ended up in the British Isles through the Alps (Otzi, the frozen caveman), or may have moved up the European coast in ships. Possibly Scythian.
In any case, the mtDNA K1b1b line has survived the Celts(?), the Normans, the Angles, the Saxons, the Romans, the Vikings, probably did NOT survive Oliver Cromwell, but came to America.
Then, since my Mom's family moved to America around 1640, K1b1b survived almost 400 years in south-central Virginia, and north-central North Carolina. That's some serious inbreeding, on both sides of the family

A serious case of Hide the women! Hide the beer!
Interestingly enough, my Mom's family were all short, stocky, black hair, olive skin. I believe that the true meaning of Black Irish may be the ancient indigenous lines of DNA which had more Mediterranean-like phenotypical features.
I posted in the K mtdna group about it, so that's where I'll pursue information on that branch.