How to achieve this photoillustration look in Darktable?

[patdavid]

@Iain actually did the whole series of steps in G’MIC with this:

Here's some kind "Lucisart" processing using G'MIC filters

This set of GMIC commands gets a very similar result. --gimp_anisotropic_smoothing[0] 10,0.16,0.63,0.6,2.35,0.8,30,2,0,1,1,0,1 -sub[0] [1] -simplelocalcontrast_p[1] 25,1,50,1,1,1.2,1,1,1,1,1,1 -gimp_graphic_novelfxl[1] 1,2,6,5,20,0,1,100,0,1,0,0.78,1.92,0,0,2,1,1,1,1.26,0.37,1.05 -add -c 0,255