“How the Athapaskan migrants were able to spread their language – and genes – so successfully is unknown.”
Maybe they talked to the women they met which might explain both.
Just some old bits of stuff off the top of my head, so may not be accurate...
The word “Apache” was used as a general term to mean enemy by many of the non Apache tribes in the area.
Navajo were called “head crushers” because of their habit of executing prisoners by dropping large rocks on their heads.
I wouldn’t know where to start in studying up on actual histories of the indig tribes. There’s so much activism and revisionism slathered all over the subject.
The above concerning Navajo and Apache is from conversations with a Marine I served with that was raised as a Navajo “res indian”. No clue if it’s accurate or not... but I would guess, from having trained with that Marine and others from south west US tribes, that the Apachean were so successful because they really took the war fighting thing seriously. Very seriously.