That said, it seems like the culling advice for RT is "expanded camera frustrum" culling, distance culling dependent on size, and choosing the right geometry LOD. Beyond that they want you to aggressively mark geometry as opaque and carefully arrange objects into groups (BLASes) according to a couple rules so the GPU can skip as much work as possible.
https://developer.nvidia.com/blog/best-practices-using-nvidi...
Rendering objects that 'we can't see' has been done for as long as shadow caster light sources have been around. Even though we cannot see the mesh directly, the light can, and the viewer can see the shadow. These indirections all play their role in the greater "rendering equation", and the specific solution depends on the constraints of the application and resources of the development team.
Some renderers have abandoned triangles altogether for signed distance fields, but this involves re-creating from scratch the entire art pipeline.