coast island

Hey friends, I’m current finishing my ISLAND terrain for a UE4 game, and I’m having trouble with the coastline of the terrain. I have already put the coast erosion but the problem is that it doesn’t seem to be real because the node by itself made a coastline with no variation and I don’t know how to make it more random in terms of size and height(like the GTA V coast for exemple).
So if someone have any ideia of how to make it work please tell me.

Thanks for the attention.