I just got a new 2019 8-core Macbook booting from ZFS, and thought I'd share one caveat:
The Wiki instructions for creating the Preboot partition don't work on newer macs. What I had to do to get it working was mount the APFS Preboot volume, and rsync everything from /Volumes/Preboot/<uuid> to /Volumes/boot
Without doing this, the system always boots into the Boot Repair utility.