Thanks guntiii,
Terrain was generated with Unreal landscape with a 1K displacement map. Since the map was lowres, I scaled it to 4K myself and painted a lot more in Unreal. Then set dressed it with Megascan models. I also placed various mountain meshes far behind the terrain based on my cameras to give more depth to the shots and make the environment look large.
Apart from the paint work and models, its the Landscape shader which gave it a nice feel.
Cheers