Dynamig Lightning Perfomance

I’m working on Open World project, and we have a very big problem with lighting performance.
Because of the large world we can’t use static light.
First we used conventional dynamic shadows, but even on the relative performance of the machines kept below 30 fps.
Then we moved on RayTraced DistanceField. There was a noticeable increase in performance, but it did not save the place where it takes more than one light source. And the more we fill our world, the lower falls fps.
Please share some experience or advice about optimizing a dynamic light. Which approach should be used for an open world?

At the moment, on the stage and present global DirectionalLight SkyLight.
Some areas of the scene are illuminated, preferably by SpotLight. Less PointLight.

Video: NVidia GTX 770 2gb



Project and world settings:

Light settings: