Shader parameter management, visibility and culling, shadow and lighting setup, scriptable pipelines, geometry shader orchestration, etc. There's a lot of work

Shader parameter management, visibility and culling, shadow and lighting setup, scriptable pipelines, geometry shader orchestration, etc. There's a lot of work involved in preparing the stuff that you'll ask your shaders to, well, shade. But I wouldn't exclude shaders from "real engineering work", they're all parts of the whole.