I've thought about doing something like this but I am only very recently getting into low-level OS stuff.

I can't remember who said this, but they called "Erlang an operating system for your code", and I think that's fairly accurate. When I build an Erlang app, I don't build it the same way as I would with Rust; I have a lot of independent gen_servers that do operate independent from each other.

The Erlang VM is (roughly) preemptive multitasking, and even each process has its own GC, so it does feel like it could be a natural fit for its own operating system without having to live on top of Linux.