Dedoimedo published a guide about how to resolve critical boot issues in Linux on a multi-boot laptop
Messed up laptop: Linux recovery
Guide showing how to resolve critical boot issues in Linux on a multi-boot laptop, due to missing /boot/efi partition as a result of wrong UUID in /etc/fstab, with KDE neon example, use of journactl, fdisk and blkid commands, philosophy around modern technologies that push solutions to problems that do not exist, and more
Messed up laptop: Linux recovery