Use AO in textures.
In a dark scene, you can do flake GI on flashlights. Last of Us did this and there’s threads about it.
You can design the scene and textures to be darker in corners, or darkener and dirtier where you’d want AO.
You probably could get away with a tiny bit of light baked in, almost ambient lighting.
Capsule shadows may be an option on key assets.