Inspiration

A lot of this looks incredible.

Beginner

Get Unreal Engine 5 here. Unreal is free. You must download epic games launcher first.

Inspiration

He added two donut torus objects, and linked the wave displacement to the z motion of them?

To copy the wave look for the torus objects  use  the copy modifier and copy the location of the points of the displacement? 

Beginner

Intermediate

This tutorial shows how to make your landscape look more natural.  He creates masks for the factors of mixshaders that define the near, mid, and far areas.   Then he changes the scale of the texture he is using for the ground.  He also shows how to use a masks for the mountains. 
 

I found this Tutorial about how to put a texture onto the edge of an object.  He uses a remesh modifier, and pointiness from the geometry shading node.

Here is a short animation using the demo objects from the asset manager demo from blender.  You can get the demo here.