@girish I didn't install anything, but I might have upgraded from 18 to 20 at some point as well as @Neluser did.
dpkg --configure -a resulted in dpkg: error: dpkg frontend lock is locked by another process, so I restarted the machine after all and updating worked fine.
Before that I killed the dpkg process and tried to run it, which resulted in that:
dpkg --configure -a
Setting up grub-efi-amd64-signed (1.173.2~20.04.1+2.04-1ubuntu47.4) ...
debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable
dpkg: error processing package grub-efi-amd64-signed (--configure):
installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent processing triggers for shim-signed:
shim-signed depends on grub-efi-amd64-signed | grub-efi-arm64-signed; however:
Package grub-efi-amd64-signed is not configured yet.
Package grub-efi-arm64-signed is not installed.
dpkg: error processing package shim-signed (--configure):
dependency problems - leaving triggers unprocessed
Errors were encountered while processing:
grub-efi-amd64-signed
shim-signed
Either way, solved not in the most elegant way, but solved 😄