C++, I am a library developer with some embedded experience. I can easily interface with c libs and expose my lib with a c interface. With clang, static analysis catches most bugs before runtime. Everything I write can be compiled nearly anywhere with very little dependencies required. Excellent IDE and LSP support with a ton of documentation on the language features available (admittedly, there are a lot). The standard library is gigantic, useful, and well documented. It is used everywhere, so resources and example source code in C++ are very easy to come by. Project configuration (via CMake) is extremely powerful and expressive (though not technically C++).
Some languages have some of the elements I listed, but no other language has them all.
If you don’t mind throwing your two cents my way, what’s a good intro to C±± book for those who already have a basic understanding of C?