Once I learned one language or feel stuck on a language, what should I do next?

This is a common question asked here. The best answer is to learn another one. Let’s say you started with C or C++ or C# and now you feel confident with those and want to learn something else, then you can learn JavaScript, Node.JS, HTML, CSS, PHP, etc. There are hundreds of languages to learn and they are always changing.

No one person can tell you where to go next. That is up to you.