This is as good a place as any to ask, are there any good documentaries about how various stuff is made that isn't entirely fluff interviews & panning over assembly lines without any explanations about the engineering involved?
It's incredibly hard to find really good documentaries, they are basically all fluff pieces as you mentioned :/ I have however good experiences with old docu's on Youtube (propably made in the 80s/90s and digitized from video casette). These kind of docu's don't have as many bad interviews as modern ones and just have more content imo.