https://antongerdelan.net/opengl/ is a decent resource for learning opengl (the author was a TA in my graphics course in college :D). And I do think it's worth Lear ing opengl over vulkan today. Vulkan dials the api complexity up to 11. If you're happy with windows only, then directx 11 would be a good choice too, but I don't have a good reference off hand.

The problem with graphics programming is that really you need to learn two things simultaneously: how 3d graphics are rendered, and how to use a GPU api. They can both be a significant thing to learn alone, and the complexity of cramming the two into your brain together makes things hard.