Roman conquest of Mauretania south of their OTL conquests there (anytime into the early 3rd century perhaps) leading to more contact and trade with the Canaries and eventually a more maritime Guanche culture. These Canarians would end up more like the Irish, being drawn into the periphery of the Roman system. Maybe they'd be converted to Christianity if Rome still converts. It's possible their seafaring may see colonization of Madeira or Cape Verde or even the Azores. But in any case, these alt-Canarians are much more incorporated into the region and even in a worst-case scenario would survive as much as OTL Irishmen or for that matter Berbers have.