You already know the basics with HTML & CSS, so I would recommend focusing on vanilla JavaScript and Node.js while keeping an eye on Deno.
React and APIs are safe bets, but make sure you understand React in the context of JavaScript and not the other way around. If you want to set yourself apart, learn TypeScript and GraphQL. As for APIs, are you looking to consume them in a front-end application? Or build an API on the back?
It sounds like your focus is primarily front-end. If you want to go "full stack", go MERN. You can use MongoDB's cloud-based Atlas or real-time Realm for your database.
I look forward to the State of JS survey results every year. This gives you an idea of what developers are using, whether they love or hate it, and what they want to learn https://2020.stateofjs.com/en-US/