I’m not saying it can’t be done, and I understand the economics can work.

I still just feel like a non-GC language (maybe even Rust) is a better choose when nanoseconds matter.

The only non-GC language that offered Java like capabilties in productivity, without being either C or C++, was Delphi, which has stuck being mostly for Windows shops, and is taited with the way Borland went through re-inventing itself.

Ada is not something that these companies would bother using, even though there are about 7 vendors still in business.

Likewise with either FreePascal or Modula-2.

Most likely a few of these exchanges are writting new code in Rust for such deployment scenarios.