This is limited by the game itself.
There is no "radius" of this feature we have already set the maximum possible.

Basically, if the game can render the chest/search point/oculus, and you are within detection range, The software can detect it and show on screen.
This is why you cannot see chests 1000m away. Unless it's rendered by game already, and you are within detection range as determined by game, sadly no chance.