NixOS is abnormal, though I don't know if it's hobbyist. But at some level OSes built on the Linux kernel will all have the same "flavor", since the kernel is T

NixOS is abnormal, though I don't know if it's hobbyist. But at some level OSes built on the Linux kernel will all have the same "flavor", since the kernel is THE abstraction between hardware and software. So if you want something REALLY radical (I know this is deviating from your original premise), you'll want to look at other kernels. Google's Fuchsia comes mind, as does PhantomOS.