It isn't unsuitable per se, but it definitly lacks the knobs of something better like D, C# or Nim.

https://www.packtpub.com/product/creative-diy-microcontrolle...

https://www.f-secure.com/en/consulting/foundry/usb-armory

Not exactly, the web runs on browsers and web engines that are written in C++, and servers that are mostly C and/or C++. On the other hand, "the could" runs (partially) on k8s and friends, which are written in Go (which runs on servers, written in C and/or C++).