I still find it very suspicious, that the .blend file with the Brushes crashes most Blender Versions, but I didn’t mean that the Brushes work fine, just that they work as expected and that they behave the same in 3.0 as in 3.5…
Omar is right about the colors of the Brushes, they are very bright. If I’m not mistaken, black in a Texture means no displacement and white means full displacement. Your Textures seem to have no black, therefor everything is being displaced.
Here you can see some great examples of Rock textures (most have a lot of black):

That’s from the Pixologic library btw.