There have been Native scholars who are actually Native. They've existed ever since assimilation was full blown in the Great Plains. I'll go through my books and name a few in an edit. We can know the opposing viewpoints from different sources, but as another user said, unless we could go back in time and really see it occur, we may not be able to discern full truth.

I know I won't get my truths from the Christian missionaries and Jesuit priests who have long been the definitive sources on the subject of defeated clan-systems.