Man, where is that first image coming from? There is an entire other thread with our attempts to recreate it:
It’s also a project I keep coming back to, cause I always feel I’m right on the cusp of a breakthrough. So far, I think I can safely say that there is no erosion used on the actual terrain itself (possibly used for mask generation, but I’ve not found those particularly useful). The bits that are cut away are likely done with Expander devices, the low-lying terrain has the appearance of an Advanced Perlin or Basic Noise device that has been fed into a Ramp device with another noise generator as the mask input for the Ramp device.
What I haven’t been able to nail down is the fragmented look. The closest I have come has been stacking Voronoi devices with the same seed at different scales, but that’s only getting me so far.