I not so versed into that debate so will gladly take input, but seeing how the “stop the world” issue seem to be for games for example, I’m cautious.
https://sourceware.org/glibc/wiki/MallocInternals
Especially relevant anything describing how mmap() and sbrk() are being called.
The matter is not if the language has a GC or not, regardless of the GC algorithm(s) being used, rather what language primitives and standard library features are available to be taken advantage of, when required to do some low level coding.
Here is another set of examples, TinyGo, TamaGo or Oberon for tiny computers.
But nobody should do that, you allocate upfront.