I was considering similar approach were I still stuck with Apple for work: make a Firecracker OCI runtime for MacOS. Fortunately Intune for Linux came around before I had to resort to that.
Virtualization.framework does most of the things Firecracker does on Linux. It's not literally the same, of course, but it does a comparable amount of the work for you. Here's an example application which uses it:
And yes, that's really the whole thing. Once the VM is configured (which is what most of the code is concerned with), running it is fully handled by the framework.
Firecracker is also the distro that makes assumptions (and therefore boot time wins) about being run inside the Firecracker VMM, as far as I understand it. You'd also need the OCI runtime, and a Docker-compatible socket would make tons of sense.
