If the show is more nuanced than that (which I assume it is), don't expect them to pick up on that. If there's an obvious character / story ark that changes the whole outlook of the series, don't expect them to grasp that either.

Thus far, there has not been a single demon that has shown regret, or compassion to their victims. There is some "material" analysis of demonic society, and that because they value might makes right (who has the biggest and most powerful mana and magic) they have not learned to collaborate and engage together. They only lie to humans and not each other. I think there's an indication that Demons saw Frieren hide her power level during a s1 episode, which means future demons might discover hiding their powerlevel, and thus have to engage in trust and collaboration.

Honestly, the series is not really about good vs. evil and fighting demons. But about love, mortality, doing good, and its consequences through the ages.