I didn't do it in one weekend but managed to get through the material in a couple weekends ;)
In fact OpenGL support has recently been officially deprecated by Apple, making the crippling official. It will almost certainly never see another feature update. It's Metal or nothing on Apple platforms for future support.
From there, I got interested in linear transformations in general, and then did Gilbert Strang's course in Linear Algebra on MIT OCW.
The first 3 chapters of "Real-Time Rendering" and all of "Ray Tracing in One Weekend" are freely available on the authors' website for free or pay what you want.
Everything beyond that is arguably just optimization.
How is Metal less explicit than Vulkan? As far as I understood they are both quite low level.