everything is there to make this reach the next level. You just need to take a photo of it with your phone and then convert to black and white. Then look at the reference and treat it like a charcoal drawing and correct the drawing in color. Your brush needs to be thought of as a charcoal pencil and it's just about getting the drawing more accurate. All the paint on the canvas is fine. Just needs more accuracy.

You are not squinting for your values, or shadow patterns. Your shadows are too light and there is not enough contrast between light and shadow. Look the attached shot. Use rapid eye movement back and forth between your painting and the photo. Look at each part individually to check. Look at the nose in your painting then quickly look at the nose in the photo. back and forth. compare. train yourself to see where you are off and then fix it. Squint when you do this too.

looks good! go back into your average shadow mixture and find the shadows that have gotten too light on you. Like the shape of the shadow under nose. Get specific and try to nail those little shapes that make up the bigger ones.

Glad you are willing to try it. If you were exhausted you were doing it right.

It’s getting there. Needs a little more to the back of the head. Compare with photo keep honing the drawing at all stages

I like how you simplified his head. Good job! the edges are not complete though. look along his cheek and down to chin , and brow where it meets shadow, all need to be softer.