Needing recommendation on a filter

You're perfectly on the right road with extrusions in Photoshop. Offset, copy, offset, copy... which is what I would have done. We could easily produce the technique right inside of FilterForge of course.

There are methods using the smudge component, but this often leads to results that don't look as wonderful. I personally think just the classic offset-copy method does a clean job extruding outwards in fact may be significantly faster than smudge with antialias enabled.

I built a small "tech demo" that I think answers your basic needs which I'm pretty sure I understood you right. This is kinda like a nice foundation so you can add more to it too. The filter just does the copy-offset method and just adds a couple parameters to help automate it. By default, it accepts images with alpha layers and utilizes that to build which ever way you offset it.

Percentage SHOULD be small values (0.1 ~ 1 works very well). I just didn't bother to put a range on each of those sliders. Shading just adds shading to the extrusion (Shading at 0 will give you a purely black shadow). Offset X and Y just gives you control which way the extrusion will go (Values between -1 ~ 1 recommended but not limited to it.) Tech Demo mode was a thing I made to test the filter. It just uses a perlin noise with alpha with high contrast to make the maps but it's really an unnecessary mode.

Hope this helps!

Offset-Based Extrude.ffxml

The current method only lets you extrude based on the original image, so there isn't much control over the output. You can only shade. If you have the pro version of FilterForge you can modify the filter by adding a simple hue/saturation node at the beginning of the tree.

It's nice because I now have a starting point for another filter.