What should I learn to become a full-stack web developer?

It sounds like you’ve got a good foundation! I'd suggest focusing on either React or Vue for the frontend, as those are really popular in the job market. React tends to have more job opportunities, but both are great choices. For the backend, since you’re familiar with PHP, learning Laravel could be beneficial. Alternatively, you could dive into Node.js to stick with JavaScript throughout your stack.

Also, remember that there’s no one-size-fits-all roadmap. Your direction should depend on the type of work you want to pursue. If you’re leaning towards startups, it would be helpful to learn some cloud basics like AWS and Docker for containerization. And definitely get familiar with Git if you haven't yet. Most companies expect you to know at least one testing framework, so consider Jest for JavaScript or PHPUnit if you stay with PHP. Just don’t overwhelm yourself—focus on one area at a time and get comfortable before moving on to the next.