I replaced Grub w/ rEFInd a few years ago and I've never looked back. The ability to just scan filesystems and boot images is so simple/easy compared to the Grub menu edit and "reinstall" process you have to go through every time you want to make a change. I've never used systemd-boot but highly recommend rEFInd over Grub.
I also have a Python script for installing Ubuntu on native ZFS w/ encryption and using rEFInd. You can use this script from a live boot environment. If nothing else, can easily review for how to do it manually.
I also have a Python script for installing Ubuntu on native ZFS w/ encryption and using rEFInd. You can use this script from a live boot environment. If nothing else, can easily review for how to do it manually.
- https://www.rodsbooks.com/refind/
- https://wiki.archlinux.org/title/REFInd
- https://github.com/rsyring/zfs-on-root/blob/master/zor.py