I love low level kernel/OS stuff but loathe the operating systems we have today. Windows, Linux, and BSD are heavily rooted in principles we designed 30+ years ago. These weren't designed with the requirements we have today - like configuration management for servers, live security upgrades, mitigating CPU flaws to name a few. POSIX has served us well but we could probably come up with something much better if we tried.
I want to see something radically different. Whether it's for desktops or microcontrollers I don't mind.
I'm aware of a few hobby projects such as SerenityOS which are cool but still very 'inside the box' in terms of design and don't really have any backing.
Really?
> like configuration management for servers
What do you mean by this? Configuration is standardized on Linux and BSD. With tools like Docker and Nix, it's arguably easier than ever to set-and-forget configuations.
> live security upgrades
Livepatching has been a thing on Linux for close to a decade now.
> mitigating CPU flaws
Microcode updates are a common occurrence, I'm not exactly sure how you'd expect people to mitigate silicon-level exploits with software like that otherwise though.
On a separate note, what you might be looking for is Redox OS. It's not corporately backed, but it does solve real, tangible problems with modern OSes like memory/thread safety.