Failed to start zfs-load-module.service - Install ZFS kernel module.
zfs-load-module.service: Failed with result ‘exit-code’.
zfs-load-module.service: Main process exited, code=exited, status=1/FAILURE
modprobe: FATAL: Module zfs not found in directory /lib/modules/6.12.47+rpt-rpi-v8
Starting zfs-load-module.service - Install ZFS kernel module…
At best install the headers meta package instead of the versioned one. Else you need to install new headers on every kernel upgrade manually:
apt install linux-headers-rpi-v8
That one depends on the respective latest versioned one, like linux-image-rpi-v8 does. So whenever the kernel is upgraded, the headers are as well, and DKMS can compile the new ZFS module right away.