I’m not sure if I’ll have time to revisit this and add a procedural rock texture so for now I’m adding in a basic screenshot:

Really love the “cavity” look in the viewport, really makes things look way better. So this was a combination of basic pushing and pulling verts either using the proportional editing option or sculpting with dynotopo turned off. After that I added a displacement modifier with voronoi enabled and just played around with the size and also the color ramp to vary up the look. I’d like to try a procedural texture for this then bake it out as a texture.