Making terrain into an earth shape

Hi, so for the past week I’ve been really struggling with something. I have a terrain generator, I can easily export the terrain to obj into blender, I can even make it in blender, but its always way into a cube shape, whereas I want it to be in the shape of the earth (as in a map), or rather different countries. I was wondering if anyone has any solutions to my issue?

You could use sculpting to flatten out and lower parts of the mesh.

I would sculpt each area of land as a separate mesh and just place them on a water plane. There is a way to make the terrain generator in blender leave the surrounding area of the plane flat so it doesn’t look like a square out of Civ5.