After learning Vulkan, OpenGL or the next shiny API: it doesn't matter. Computer graphics and 3D math concepts don't change across APIs. The concepts you learn and make GPU do things is the same. Just the language or dialect differs. I started with OpenGL, but I now program in D3D, WebGL, etc. Learn the basics, avoid the religious wars.
In fact when learning something not as complex as Vulkan will help, since lots of noise (boilerplate) to hide the signal (cg concepts).
https://legends2k.github.io/note/cg_resources/
After learning Vulkan, OpenGL or the next shiny API: it doesn't matter. Computer graphics and 3D math concepts don't change across APIs. The concepts you learn and make GPU do things is the same. Just the language or dialect differs. I started with OpenGL, but I now program in D3D, WebGL, etc. Learn the basics, avoid the religious wars.
In fact when learning something not as complex as Vulkan will help, since lots of noise (boilerplate) to hide the signal (cg concepts).
Cheers!