I do graphics programming for Planimeter (https://github.com/Planimeter https://github.com/Planimeter). Even when you use game engines, you still actually have

I do graphics programming for Planimeter (https://github.com/Planimeter https://github.com/Planimeter). Even when you use game engines, you still actually have to understand some OpenGL/Vulkan/DirectX/Metal level details. If you understand one of the standards, the knowledge carries over to others. Most game engines will abstract away shader attributes, but if you're not aware of how to define them, you're probably not writing them, either. So even if you're not touching glGetAttribLocation/vertex attribute APIs, you still actually have to know how to use them. Otherwise, the assumption is that you're only ever going to be able to use basic predefined rendering information exposed from the host game engine. There's a bunch of other information like that which you have to be somewhat aware of once you step outside the bounds of "just draw this for me" with the host's default shaders.