The Norse in Vinland manage to get a permanent settlement on Anticosti Island around 1000 AD, though they don’t expand off it. They introduce European diseases to the Americas given the increased presence, over the next few centuries they become endemic across the continent and the native American population rebounds to where it started. The Norse in Vinland never manage to expand their permanent settlement but do retain some links+contact across the Atlantic with Europe. Shipbuilding skills spread around to neighboring people.
Meanwhile, some endemic American diseases grow deadlier thanks to mutations.
Columbus lands in America in 1492 as in reality, and takes some Taino people back to Spain after. The American disease rapidly spreads across Europe and has a devastating effect, killing 95% of the European population and spreading beyond Europe too.
The crippled and near-uninhabited European continent is resettled by Native Americans, including Taino people settling the Spain area and the British Isles being settled by Inuit, Mikmaq, and Beothuk.
