I first saw the movie years ago on Amazon Prime.
I clicked on it on the basis of the title, not really knowing what it would be about.
I was baffled at first as I was thinking, why is this guy speaking Russian with a Serbian accent?
(There are English captions available.)
Regarding the Chechens, I was told they deliberately marked themselves as such for the obvious reputational reasons.
As you surely know, both sides now make frequent use of MultiCam.