Why is there no nudity in Darling in the Franxx?
Personally, I think it's because Darling in the Franxx is mainly about romance and action. They were mainly talking about the love between Hiro and Zero Two, so I don't think it's necessary for them to show nudity. Also, even if Darling in the Franxx is not for small children, it shouldn't show nudity, because the genre is not ecchi.