I don’t know if it’s the scientists themselves, or how it gets reported to schmucks like me in the sources I see, but it’s always seemed kinda FUBARish to assume a one time event from a single path or source for the original populating of the Americas.
I also tend to heavily doubt that our current “indigs” are descended from the originals.
So at least we have some reason to believe the Chippewa, Iroquois and Cherokee may be descended from the "originals".
We can trace back the Na Dene (Navajo, Apache, Aztec) to the very same Yakuts who provided the ancestry to the Japanese royal house and the Daimyo (these are the non-Jomon invaders from the mid 6th century).
More recent work ties the Yakuts, also known as the Sakha, to the tribe by the same name that conquered much of India around 300 BC (from Nepal). Buddha was a Sakha.
Because we now have DNA analysis available, and super computers to assist in translating ancient documents, we know tremendous amount of information about the Yakuts we didn't know just 2 years ago.