Metal is a lower-level API, somewhat similar to Vulkan or Direct3D 12. OpenGL supports driver extensions that can be used to reduce overhead in a similar manner

Metal is a lower-level API, somewhat similar to Vulkan or Direct3D 12. OpenGL supports driver extensions that can be used to reduce overhead in a similar manner to Metal, but this is largely a moot point when it comes to OpenGL on macOS, as many such extensions are simply not available.