Maria Callas-classic or dud?

I would have thought for sure someone would have posted the trailer for this:

https://www.youtube.com/watch?v=3xmsGzhhDGE

I'm hardly the target audience--my operatic knowledge is the usual lowbrow mishmash of ELO, Bugs Bunny, Raging Bull, Seinfeld, etc.--but I think I was able to appreciate the magnitude of her singing. (Thought of something else: the amazing scene in Todd Haynes' Mildred Pierce remake where Kate Winslet listens to her daughter on the radio.) If I ever knew about the Callas/Onassis/Jackie love triangle, I must have forgotten--what a story.