Making C better led directly to C++. There is no defensible reason for a programmer competent in C to choose it over C++ for a new program. All it takes to start is file names with a *.cc suffix, and the right compiler. If you don't like some feature in C++, you are not obliged to use it in your program. But the prospect of faster, more reliably correct programs written more quickly is a benefit you cannot rationally justify avoiding. Pottering about with hacks on C to help you catch problems that C++ already eliminated a decade ago is a tragic waste of your short time on Earth.

Learning Rust would certainly slow you down, for a while. Rust is mostly an opportunity for the next generation of serious programmers, and those who will teach them. But before you know it, the most interesting programs will be coded in Rust, and you will need to know it to read them.