https://www.vulkan.org/user/pages/09.events/vulkanised-2025/...
Time in Vulkan or OGL would barely register against IO and memory when loading such scenes.
It’s all gonna come down to how fast is your IO and how fast is your memory. 6 secs to load all that data, be it via vulkan style threaded submissions or OGL style threading via shared context and syncing, is not likely to happen on most laptops. Even workstations may struggle to read in and generate the necessary data. Most of the reading and generation stage is usually happening entirely outside of the gpu. All of the reading. And most of the generation. Both are going into main memory first.
Again, generation will be way faster than read in assets, but most of the assets would be getting read in. That’s IO before you even make a single vulkan or OGL call. No way around it.
Test: Start Blender, open scene, final viewport 3000 objects, 550 materials, 200 images