Right, it's "just" a VM like Multipass which is another alternative we use in the faasd project for developing against containerd on Macs. You need a full Linux host.
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.
WSL1 is still a thing. And you can't compare it to wine. WSL1 is a masterpiece and wine is, quite understandably, problematic. If only because they have to reverse engineer it.
WSL1 only has to reimplement the Linux syscalls. Wine has to reimplement the entire Windows API.