C++ powers the software where speed is not negotiable: game engines, trading systems, browsers, operating systems, and most of the embedded world. It gives you direct control over memory and hardware, which is its whole point and also why it takes longer to learn than Python or JavaScript. The two free courses here pair well. Start with freeCodeCamp's 31-hour beginner course for a full walk through syntax, pointers, and object-oriented basics, then step up to MIT's Introduction to C++ (6.096) for the more rigorous, assignment-driven treatment. Who should learn C++? People headed for games, systems, or performance-critical work, or anyone who wants to understand what higher-level languages hide from them. If a first job is the near-term goal, a faster language gets you there sooner; come to C++ when the low-level control is the actual point.
MIT's introductory C++ course. Covers C-style fundamentals, classes, inheritance, polymorphism, templates, and the STL. Includes complete lecture notes, assignments, and quizzes. All free on OpenCourseWare.
freeCodeCamp's 31-hour C++ course by instructor Daniel Gakwaya. Covers syntax, classes, OOP, templates, the STL, modern C++ features, and memory management. Build real projects throughout. Completely free on YouTube.