I recommend to try using Stationary Lights with Static Meshes, so that the shadow can be burn in the Light Map, but any of these solutions could work for you!
A quick fix to this is not a very optimized approach but yo can try. Export your 3d model to a DCC tool like blender and add a big scale plane below the surface that will be not visible in your game env. Then import it in unreal and you can see the shadows.