My current goal is: Improve my shading and rendering of light
That face is the most delightful, cross hatched sensation. That's an excellent job on your rendering of shade and light.
My littest bit of some improvement is to just go online to https://www.richardschmid.com/Alla-Prima-II-By-Richard-Schmid-p/skuap.htm and pick up a copy of Richard Schmid's Alla Prima II online. There you should be able to get into the values.
The premise behind this is because, it can and will be able to get you into the value patterns from the broads to the subtlest tones.
Good luck to your goals.
Very good drawing. You remembered there is s skull under the outside skin. Many make the back of the head flat. You did not. The ear is a little too far back in the profile view. I looked at your other drawings. Excellent. Keep up the good work I have seen in your works. With each work you will get better. Practice makes better.
I can see you know how to draw realistically. I think you are making the same mistakes as I do with head. Not measuring the distance between the eyes, nose and mouth. It would be helpful to see everything as shapes... Including the hair.