Some movies hit you over the head with an anvil. Some use a scalpel. Some movies like to preach at you and some like to ask questions and invite reflection and examination. Most people are either plot driven, character driven, or vibe/setting driven. I'm a character guy myself, but ultimately you like what you like. No shame in that.
Sure - Zone of Interest wasn't introducing a brand new concept. But what I liked about the film is how it went about showing its point. The sounds of Auschwitz were going on constantly - did you key in on them, or did you eventually find yourself adapting and tuning them out? We know Nazis are evil - but that evil is presented in a different way. The family is otherwise ordinary, but for the absolutely confounding fact that they seem totally unfazed by what is happening all around them. Grandma only lasts a few days before having to bail, so we know that the awfulness of what is happening is perceptible to others. So why are these people so immune? Dad is consumed with advancing his career. He wants recognition for his work, more titles, more respect, more worth. Mom is invested in her kids and is willing to go to great lengths to ensure they have the best environment to live in, according to her eyes. Wouldn't you agree that the pursuit of professional success, and the way parents get myopic and absorbed by what they perceive to be the best for their children, transcend Nazi Germany and would be in operation today? If so, what are some things that your are absorbed in? What is distracting you from the presence of evil around you?
I get why this film might not be liked or leave someone feeling it is lacking in plot, but to reduce it "banality of evil, I get it" is to do a great disservice to what makes the film worthwhile.