Radiance of Annihilation -Disorder Eclipse-

A government employee and his partner are supposed to keep old-world weapons out of criminal hands. Instead they get dragged into a conspiracy that decides whether humanity gets a future at all, and the mission stops looking like law enforcement fairly fast.

The plot runs through turn-based fights and a slow, deliberate slide into corruption, with the story told largely as a voiced kinetic novel rather than something you steer. Combat exists, but it's the framework the fall happens inside, not the point of the game.

Expect the protagonist's authority and body to erode scene by scene as the conspiracy closes in, with a female or futa lead depending on the route. There's a lot bundled into that erosion, and the game doesn't soften any of it.