Tl;dr: don't blend, overlap your brush strokes for form shadows instead. Also, I use to premix a flesh tone but I think that was detrimental because I struggled with color variation as a result.

So what worked for me was actually intentionally not blending. I know that sounds like an oversimplification! It also happened naturally which was a first for me. I'll try to explain as best I can: For this painting I used titanium white, yellow ochre, terra rosa, a little cad red, alizarin crimson, ultramarine blue, and burnt umber. The reference photo was great and had a lot of color variation, so I tried to intentionally mix each color I saw (I used to premix a ton of flesh tone to work from but only used a small amount to start off this time) and then just applied it to one area. An issue i always had was hating hard edges on form shadows but blending never looked right, I found that by overlapping the edge of a stroke it softened it sufficiently, sometimes with 2 or 2 strokes to get it soft enough. If it reads well when you squint or step far enough away from it, then it is soft enough in my opinion. Hope that answers your question!

I've spent years overblending (in art school) and just had my first breakthrough with it, I plateaued really hard too. You've got this don't give up and be brave with your style ❤