Very good render overall! I liked the lighting and atmosphere of the nature.
I’m a beginner for Octane but according to this manual, displacement is more limited than Cycles (Cycles doesn’t have those limitations mentioned).
It’s good that Octane have option for level of detail in the node without the need for subdivision modifier but I’m not sure if it subdivides the mesh depending on the distance of the object to the camera as Cycles adaptive subdivision does.
If you are not satisfied because of the resolution of displacement, you may want to reduce the dicing scale in the subdivision modifier.
Also I noticed something that looks like terminator artifact in your trees that might be tackled by adding more geometry to it.