I remember over 20 years ago reading an article about the possibility of humans having come over much earlier than the Bering straight. There was a possibility that Polynesians somehow made it across in their little boats.
As I recall, there were arguments made that the proto-Siberian migrants would have come over and basically taken over the continent from anyone who was already living there.
To an extent, that could make some sense. One thing the pre-columbian Americans really did well was cultivating crops -- to the extent that the rest of the world basically lives off of the foods they domesticated, such as potatoes, peppers, corn, tomatoes, chocolate, and more. We know that some polynesians did similar things and so for example we eat bananas which were similarly cultivated and domesticated. It would make sense to me that the sort of technological innovation of plant domestication came over from polynesia and that's how we got all the wonderful foods in the americas.