How baked in is the light position? I'd imagine it's possible to rotate the light in editor but not change it's height (without some work in Blender).
Long optional explanation:
I say that because I think Memileo sculpted the actual brushstroke in Blender (https://krita-artists.org/uploads/default/original/3X/5/7/57...) and rendered lighting at different angles, and exported each as an image.
Each rendered image becomes 1 frame of the "animated brushtip", with the option that each frame matches "direction" rather then being "incremental", and thats how you get the faux-light!
The cool thing is that you can extract and edit the animated brushtip in Krita e.g. this one "https://github.com/Draneria/Metallics-by-Draneria_Krita-Brus..."
Which means theoretically, you could use photo editing to change the height I think!