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!