I've only only lightly dipped my toes into the webGL landscape, but I can definitely vouch for this man. I love the way he explains things. He's like the Carl Sagan of WebGL. I'll see if I can dig up a couple resources from my own foray drop them in this comment below.

EDIT: here are the links as promised.

1. https://thebookofshaders.com/ (mentioned above, I think)

2. https://threejs.org/docs/ (of course)

3. https://docs.pmnd.rs/react-three-fiber/getting-started/intro... (optional; good for React and those comfortable for maybe don't dive right in until you get a good grasp on Three.js)

4. https://threejs-journey.com/ (a paid course with some good intro lessons as freebies)

Hope this helps!