Yeah this has been a long running complaint since ue4 came out, maybe before that too, but I was busy doing photorealism on cryengine at the time so I wouldn’t know lol.
Hopefully Epic builds up the will to do something about it eventually vOv
As for your thing, try my model if you haven’t already. As long as you’re dealing with just one light it looks like it should do what you want. Otherwise you could try playing with the post processing lighting buffer curiosity I mention in the OP to try to build your own shading off of that if you need something involving multiple lights.