Vulkan and Metal seem great.
To get started in 3d graphics all you really need to understand is how to multiply a bunch of 4x4 matrices together. From there it is a matter of learning how to put that to good effect.
Physically Based Rendering Book
Shader Toy - Build and Share your best shaders with the world and get inspired.
NVIDIA GeForce RTX - Official Launch Event (2018)
Thread on Bezier Curves
Writing to framebuffer
GUI Development is broken (2018)