Resources on Web Development Fundamentals?

My background is a Python backend developer. I know most of the finer details about how objects work in Python, how the type system works, how the code is run when it's interpreted, pip package resolution, etc. Essentially, I have an idea of how Python works beyond just writing Python code.

What are resources where I can learn something similar for React development? I'm pretty proficient with building simple React applications. Now, I want to learn more about the finer details of how SPA apps are loaded in a browser when you land on a URL, dependency management with yarn/npm, OAuth, DOM manipulation, lazy loading internally, etc. I want to have a strong foundation to understand web development beyond just React.

The problem is, I'm not sure what to look for so I can't simply Google each of these things up one at a time. If there's a concise O'Reilly book or an online resource, I would love to learn more. Thank you!