Build the concept from people, not genre
Starting from a genre or setting tends to produce a story you have seen before. Decide first what the protagonist lacks, the event that shaped them, what they will not give up and what they hide. Then place a counterpart who answers the same question differently. The question the story asks the reader emerges from that contrast.
Choose the setting last. Pick the place where that life shows most painfully, and the setting becomes part of the story rather than decoration. Write the title and synopsis only after this is settled.