I put together a shadergraph material for our synthetic humans project focused on two key areas.
Ethnic diversity and Artist simplicity.
The skin material only needs a greyscale "face texture" (which was procedurally blended together from multiple unique scans into a new face) and a normal map (procedurally created in a similar fashion as the face texture), which meant that artist only had to focus on the saving out a normal map and a good color map.
Colorization and smoothness were handled in material with colorization having parameters for both main skin tone and subtone for further variance in a color.