Having said what I said before, if you get good at knowing how to use your weapons, you take an agile posture and move a lot, find cover, run away for a bit, then come back when the NPC thinks all is good. Sniping is very effective. This is why the Vintorez was my favourite weapon, careful approach, patience, and POP, done.
And the AI in this game is well written. Sometimes it feels like you are facing real humans.
I prefer to get up nice and close ^^