Yes, the limited runtime is what is prohibiting me from using, say, Python. Runtime-wise, C++ would be fine. It’s the other reasons I listed which makes me not use C++ in this case.
Is C++ -> C interop your only reason for avoiding C++? If it is then you might reconsider C++, because calling C code from C++ is usually as easy as wrapping the #include in an extern "C" block.
I know it’s easy to call C functions from C++. That’s not the issue. The issue is that since all the API functions are in C, the code of my program will mold itself around those APIs, and my program will therefore have a C “shape”, so to speak. And the small pieces that remain C++-shaped might not be large enough or provide enough architectural benefit for the drawbacks of C++ to be worth it.