GRUB2 works fine with /boot on ZFS, however GRUB cannot detect ZFS dataset with native ZFS encryption (see bug[1]). The best KB right now is probably OpenZFS documentation[2] and Arch Wiki[3].

I've been using ZBM since its inclusion in void-packages. It already does everything I wanted it to, but I don't think its usage is widespread outside Void Linux community just yet. Being dependent on Dracut might be one of the reason why (I believe Arch is still using mkinitcpio). There's installation instruction for Void and Debian Buster on ZBM GitHub[4]. I used to have a separate ZBM root for void-musl and void-glibc which worked quite well (though I'm now running only void-glibc due to Nvidia).

[1]: https://savannah.gnu.org/bugs/?func=detailitem&item_id=58270

[2]: https://openzfs.github.io/openzfs-docs/Getting%20Started/ind...

[3]: https://wiki.archlinux.org/title/Install_Arch_Linux_on_ZFS

[4]: https://github.com/zbm-dev/zfsbootmenu/wiki