Hi, I'm author of Jotai, an atomic state management library for React. Jotai repo at GitHub
Jotai's API is fairly easy to learn if you have experience with React hooks, and you can use it without understanding how it internally works. If you have better understanding, it may open up your possibility.
To help understanding of how Jotai works internally, this includes a simplified version of core code. Its features are limited, but it's a complete implementation. The "Simplified Jotai" code has some annotations, which should help reading the code. Readers are expected to already have good understanding about Jotai's public API.
110-line code and annotations
19-min walk-through video (MP4 format)
A small example to run the code
110-line code with annotations, 19-min walk-through video, and a small example to run the code.