In 'love interest zone novels', the theme of redemption through love is quite common. A character who has made mistakes in the past finds love and through that relationship, they are able to redeem themselves. Another theme is arranged - marriage - turned - true - love. Characters are initially forced into a marriage by family or society but then gradually fall in love. And the theme of star - crossed lovers, where external forces like fate or circumstances keep the lovers apart, is also popular.
The Zone of Interest is purely fictional. The plot and characters were crafted to tell a unique and engaging tale, not drawn from real-life events. The author likely wanted to explore certain themes and concepts through this fictional setting.
It depends on the specific context. If it's described in a fictional setting or involves made-up elements, it's likely fiction. But if it's based on real events or facts, it could be non-fiction.