A little test I did for some atmospherics, along with an environment workflow that involves Houdini to a reasonable degree.
The base terrain height map was created in Gaea, then a portion of that was imported into Houdini where the rocky cliffs were created
The cliffs were then exported, and then the scene was constructed and rendered in blender
List of where everything was created:
Terrain: Gaea, cliffs in Houdini
Foliage: Speedtree, scattered using a custom Geo Nodes setup in Blender
Clouds: Simulated in Houdini, VDBs rendered in Blender
Textures/Rock meshes: Quixel