EDIT 2024-02-18: Solved! JohnnyMac was right, I have no clue why, but the boot priority changed and the reboot after the update caused the issue to manifest. I have excluded the device from the bootable devices in the BIOS and it boots again.
I figured out that it was an issue with my external USB dual bay HDD enclosure. It doesn't boot when it's plugged in, even after removing it from /etc/fstab. It doesn't even reach the GRUB menu when plugged in. It only displays a blinking cursor, doesn't allow switching the terminal with CTRL + ALT + FX but does restart with CTRL + ALT + DELETE. It's able to reach emergency mode when the device isn't plugged in and is able to boot fine if it's removed /etc/fstab. Does anyone know what could be causing this issue? Everything works fine when it's plugged in after booting up the system.
These were the packages updated:
- base-files
- bind9-dnsutils
- bind9-host
- bind9-libs
- fish
- fish-common
- gnutls-bin
- libcpupower1
- libcryptsetup12
- libgnutls-dane0
- libgnutls30
- libisl23
- libnss-mymachines
- libnss-systemd
- libpam-systemd
- libsystemd-shared
- libsystemd0
- libudev1
- libunbound8
- libxencall1
- libxendevicemodel1
- libxenevtchn1
- libxenforeignmemory1
- libxengnttab1
- libxenhypfs1
- libxenmisc4.17
- libxenstore4
- libxentoolcore1
- libxentoollog1
- linux-cpupower
- linux-image-6.1.0-18-amd64
- linux-image-amd64
- ovmf
- qemu-block-extra
- qemu-system-common
- qemu-system-data
- qemu-system-gui
- qemu-system-x86
- qemu-utils
- systemd
- systemd-container
- systemd-sysv
- systemd-timesyncd
- tailscale
- tar
- tzdata
- udev
- usb.ids
- usbutils
- usr-is-merged
EDIT: Quickly plugging it in after GRUB has loaded seems to work.