Yes, I already run the native build of macOS in a bespoke hypervisor for experimentation purposes (most of the hardware is passed through), and macOS already ha

Yes, I already run the native build of macOS in a bespoke hypervisor for experimentation purposes (most of the hardware is passed through), and macOS already has a VM-specific ARM kernel that in principle doesn't even require any proprietary CPU features and would run on any ARM machine (the native one wouldn't, it needs custom Apple instructions). I'm pretty sure someone already tried the macOS vmkernel on QEMU/KVM on another ARM box and it boots to a shell. I think it even has virtio support and there's a QEMU Guest Agent built into macOS these days (yes, really). There's just one catch. The desktop environment requires GPU acceleration to even start, and your two options are emulating the proprietary Apple GPU, or emulating the paravirtualized Metal GPU they developed for VMs. Neither is likely to be particularly easy... it's why I tell people to not expect to be able to run a macOS VM on Linux on an M1 Mac, unless they want to write a whole Metal implementation. A plain kernel in single user mode? Sure. macOS desktop? Good luck :-). For macOS on macOS on Apple hardware, Apple have their paravirt GPU support on both sides so it basically "just works" with minimal work from the third-party hypervisors that build on those frameworks.