Earlier quoted context omitted.
WSL2 is a simple virtual machine. Nothing you couldn’t do on macOS with e.g. multipass.
It's really not. With WSL2 the kernel runs in a VM, but user-space programs do not. As a result, CPU-bound programs suffer close to zero overhead compared to running natively on linux. AFAIK, there's no way to achieve anything like this on macOS.
But in WSL2 the whole thing runs in a Hyper-V VM, with a customised Linux kernel (available via http://linux.microsoft.com) to help with interoperability between WSL and Windows.