I play every stealth game the same way.
I remain at a distance. I find the higher ground. I use a weapon with a scope; a bow and arrow if one is available, a normal sniper rifle if not. I crouch-walk around my target or targets slowly, attempting to pick off each enemy and objective in turn, such that no one ever notices anything is amiss until the instant when they’re killed. If they do notice and sound the alarm, I do not care; as long as they do not know where I am, and so can never fire at me, I continue until the job is done. It’s always this way. In the Far Cries, Crises, Splintered Cells and Rainbows Six; wherever possible, this is how I play.
I am playing Metal Gear Solid V: The Phantom Pain differently and I don’t know why.