Can you recommend a good entry point into the theory/math behind these? This is one of those true "wtf, we can do this now?" moments, I'm super curious about how these are generated/created.
Oof, there's a lot of machinery here. It depends a lot on your academic background.
I'd recommend starting with a tutorial on neural radiance fields, aka NeRF, (https://sites.google.com/berkeley.edu/nerf-tutorial/home) and an applied overview of Deep Learning with tools like PyTorch or JAX. This line of work is still "cutting edge" research, so a lot of knowledge hasn't been rolled up into textbook or article form yet.
