Thanks for the reply. I had no success with Wellfound (formerly AngelList Talent) and WorkAtAStartUp, and Monthly HN Hiring. I cannot be sure if /jobs is going to be different, but I will have a look anyway.
Just remembered. There's People-First Jobs as well. Doesn't seem to be a lot of Functional Programming (FP), system-related posts, but just wanted to share another resource:
https://stackoverflow.com/jobs/companies
As well, ask some friends to forward you their job links on LinkedIn, if the request would be well-received.
I'm not sure, but functional programming with systems programming seems pretty niche.
Have you also tried contacting research folks in that area? It's kind of a cold call, though. But they may know someone at Commercial Corp.