Transmigrating to Ancient Times as a Spy

Not a Martial Arts World Where All the Settings Are Fused Together. I Want a Fictional Dynasty

Any recommendations similar to "I Really Run an Orphanage, Not an Assassins' Den"? The protagonist transmigrates into an ancient martial arts world, and the System rewards him with special skills. It must be an ancient martial arts world, not a modern setting, and no cultivation, either.