The second of the very short list of SF plots is offworld envoy/ambassador/investigator sent to planet Zod, which has a strange culture, and gets caught up in solving a crime.
Examples would include Moon Moth by Jack Vance , one of the Ancillary trilogy by Ann Leckie, and the 2020 Hugo winner, the satisfactory Memory called Empire, LHoD by Le Guin, Stranger in a Strange Land, maybe, Emabssytown by China MelvilIe, many Iain Banks books and so on.
Anyway, I'm reading Memory called Empire and it is fine. The planet is an Aztec/Inca style civilisation which has very successfully conquered much of the surrounding branch of the galaxy. The stranger is from a spacer planet system not yet acquired by the empire, and is an ambassador replacing the previous one who spoilers has just been murdered.