The development libraries are separate from runtime drivers. Your offline dev machine still needs the GPU driver from Part 3.
Since OpenGL 4.6 is vendor-specific, follow the instructions based on your graphics card. opengl 4.6 download offline installer
There is no universal OpenGL 4.6 installer from Khronos Group (the governing body). Khronos provides the specification, not the binaries. The only way to get accelerated OpenGL 4.6 is via GPU drivers. The development libraries are separate from runtime drivers