My display was not damaged. Switched back to an older kernel version and it was fine.
As another commenter mentioned, fancy pants filesystems that support snapshots simplify this situation.
This is what I used. zfsbootmenu is an EFI executable with support for doing zfs rollbacks (and any other arbitrary zfs command) so as long as my EFI partition is left untouched, I don't need a livecd or another partition or anything.
Maybe just didn’t want to boot on faulty kernel at all, now that the risk of permanently damaging the display was known.