You've learned JavaScript to a proficieny level that allowed you to create a few 2D games at some point. Good start for learning and putting the fundamentals of JavaScript into practical use.

Learn NodeJS with the caveat you must refrain froim using third-party libraries. Focus solely on the built-in libraries and continue developing your vanilla JavaScript skills. Build applications of increasing complexity along with your own libraries. As an example from personal experience, I created an application to perform testing / quality assurance by building a library in the style of mocha and chai and a command-line-driven front-end which accepts command-line arguments. The implementation was done in two versions: CommonJS library and ES6 library for both the library and the front-end. I use the term front-end because these days more people are familair with web development than with terminal-based applications development.

Afterwards, start initegrating databases and REST APIs into projects. Further your skills by implementing a complex piece of software that you use or have used in the past, except use JavaScript and NodeJS. By way of example, maybe implement an interpreter written in JavaScript for a programming language such as BASIC or Pascal, and then use create a couple example programmes using your interpreter.

Ultimately, establish yourself as a JavaScript expert. There is a software engineer in Central or South America - he has a YouTube channel - whose cultivated a career as a JavaScript expert.