I first saw ‘Koyaanisqatsi’ in 1985. Stunning. Haunting. Life-changing.
Set me on a path.
As for recommendations, all that comes to mind at the moment is a documentary from around 1990, directed by Alan Eirera called something like A message from ‘The Elder Brother, about the Khoggi Indians of Columbia.

I doubt that I could propose an ‘essay film’ relating to any that you have mentioned but one film i’ve watched recently that could perhaps classify under the title is American History X. Good film.

#1 Why do you care about “essay films”?

I have many but they sound way less interesting when described this way.