Citation needed, particularly for Nature. As far as I can tell the supposed disparities are explained by the amount of violent crime the race and ethnicity commits (leading to more police interactions), but it's impolite to bring that up.
Again I have yet to see any convincing data that supports this. There's a marketed list of names of victims, some with video footage, but I can also show you names and video footage of non-violent victims of other races being killed by police.
I certainly support police reform (within the bounds of common sense), and continuing to try to lift black folks up, who I agree have been systematically discriminated against for hundreds of years. But doing it under false pretenses has already opened up a Pandora's Box of racist moral panic when it's simply not there.