Just vm’s? No syscall emulation?

Microsoft abandoned syscall emulation with WSL2.

The differences between Linux and XNU might be less problematic, since it's a Unix derivative.

But as Wine shows, it takes a lot of work and you still get a suboptimal, buggy experience.

This is what I was hoping, I know there is irreconcilable differences between NT and linux kernels, but maybe there is hope on XNU.

I'd be surprised if there weren't already something out there to do this. Darling [1] already translates in the opposite direction with little difficulty; I'm not aware of any fundamental reason that you couldn't emulate Linux syscalls on XNU.

[1]: https://github.com/darlinghq/darling