Yes, I have read Sapiens. I have read a lot of other things as well, including the critiques of Sapiens and more recent works that blow huge holes in some of his assumptions. A lot moves on in 10+years.
So please do elaborate - what is the murder rate amongst non-contacted indigenous people? Because any contacted indigneous people are tainted by their very contact, and the place that puts them in our "modern" world.
"Also looking at our own past, people were much more violent in early human societies" - you are assuming that people who have had no contact with the modern world are violent because (allegedly) we were more violent in the past. Of course, without patriarchal hierarchies and nation states, they may be less violent that we have ever been. You cannot compare what we have been (or currently are) with them because you don't know what they are like.
"Things like infanticide were thought to be common" - who thought these things? What was their evidence?
You are falling into the trap of having read a couple of Eurocentric books full of suppositions, which are almost impossible to evidence - forensic archaelogy is a fascinating study which changes opinions more often than I change clothes - and whose observations are inextricably overlaid by modern society. Even if they are right about all that, there is no reason to assume they are right to apply those things to an uncontacted Amazonian tribe in 2024.
It is arrogant to assume that abuse and violence are common amongst people that we know absolutely nothing about; and in fact many tribes in the Americas had sophisticated social structures, complex systems of social justice that dealt with violence (often in ways better than Europe ever has), matriarchal sytems of organisation and many other benefits. Native Americans were not the savages settlers and Europeans would like to portray them. The fact that we might have been pretty savage in our past - in some ways still are - does not mean that is the natural way in which human society must develop and evolve.