C wins by far. I was quite a fan of rust before but came to realize that it has the exact same issues as C++ just shown differently. Cross compatibility is often bullshit unless your program is a "Hello world", each dependency is like 200mb of pure shit, and each dependency has 8 others.
C on the other hand is faster, simpler. It can be painful when dealing with memory. You see the thing with C is that the syntax is simple, but you get no object-oriented anything. No this, no that, no classes no abstractions. This can be a slight issue and extend the size of your code aswell as the order of it. I would choose C since with C you can make sure your code is fully portable.
Most libcs such as cosmopolitan, or the more widely used GNU libc focus on your code being compatible and portable, to be run anywhere. This is a great advantage with C but you will often have to use macros to switch between shit depending on the OS.
shitting rn