An interesting point. Personally, I saw her relationship with Cesar as essentially a metaphor for how Coppola viewed Eleanor (his late wife), casting himself as the misunderstood genius and her as endlessly understanding and supportive. It's touching on one level (the film is dedicated to Eleanor) but my giddy aunt, I found the film itself insufferably boring and pretentious. The best thing I can say about it is there are a few interesting images and the design work is good (costumes, sets, etc). But dear Lord it's dull, humourless, witless, pompous, and completely up its own backside.

My full thoughts are here, if you're interested (possibly not, given your thoughts on the various scathing takedowns of this film, but rest assured this is my considered opinion, not me leaping on a bandwagon).

Film Review — Megalopolis | Simon Dillon Cinema (medium.com)