pacman -Syu net-tools
pacman -Syu linux-headers linux zfs-meta
and the zfs seems to build for a LTS kernel, but not for the current installed kernel:
(2/4) Install DKMS modules
==> dkms install --no-depmod zfs/2.4.3 -k 6.18.40-1-cachyos-lts
==> dkms install --no-depmod zfs/2.4.3 -k 7.1.5-1-cachyos
==> WARNING: `dkms install --no-depmod zfs/2.4.3 -k 7.1.5-1-cachyos' exited 1
==> dkms install --no-depmod zfs/2.4.3 -k 7.1.5-arch1-2
==> WARNING: `dkms install --no-depmod zfs/2.4.3 -k 7.1.5-arch1-2' exited 1
Seems like this is one of those times where ZFS is out of sync with the kernel release, so maybe running the LTS kernel is better.
Edit /etc/default/grub and change GRUB_DEFAULT to point to LTS image, then run
grub-mkconfig -o /boot/grub/grub.cfg
gpasswd -a rob vboxusers