Learn to do Cryptography with Python and for free too. A course by computer scientist of ETH Zürich and cybersec expert Cyrill Gössi. He teaches the concepts of Cryptography with a practical approach.

All of those are lists of why what appears to be simple in C++ ("just" create a std::mutex at global scope) are in fact not simple at all once you consider the details. It's just that C++'s (and C's) ...