I also wrote about this after I saw the documentary. Perhaps you might find my take interesting as it has several overlaps with yours. I think Rachel demonstrates a very central edifice of white supremacy: the baked-in working assumption that blackness is an inherent state of pathology.

More here: “The Rachel Dolezal Divide: Blackness as a Forced Classification and a Subsequent Cultural Genealogy” by Moses Mphatso https://link.medium.com/hcAf38PReX