^ I’m guessing Unreal’s Depth of Field settings should get the job done with the Near Region / Far Region parameters, if I understood this effect correctly. I tried something similar in this earlier video of mine; not tilt shift or anything (I didn’t even know such a thing existed till today!), just some DOFs which I used to draw the eye to the subject matter just like you suggested. I did DOF manually for that video though, a real-time system might need to figure out things like what the player is looking at (object of interest on the screen maybe) and deduce the DOF region parameters based on context.
Whether I want the player to feel like they’re looking at nature through a camera lens like a photographer or as if they’re actually there is also something to think about I guess.
BTW - thanks for the effort you spent on the example pic, it does look better with the spider brought into focus. And that photograph of the two bees around yellow flowers you linked - absolutely gorgeous! That should keep my inspiration tank at healthy levels for a while!