Here my is process for creating a wax resist textural effect in Procreate. Can be performed in any drawing application with these conditions:
Divide filter(s)
Semi-Transparent/Rough Brushes (or that do not lay down full opacity)
In this video:
Quoll brush in Artistic Section (Built-in)
Shale in Calligraphy Section (Built-in)
Originally uploaded as a short, I got a request to make this horizontal for better legibility of layering, pausing etc. The comment is gone but hopefully this helps out!