I cannot login to my laptop since the last update 2024-01-13

[stephane]

dbus-broker is missing
see : [Stable Update] 2024-01-13 - Kernels, Systemd, Qt5, Mesa, Dbus, Firefox, Thunderbird

can you

sudo pacman-mirrors -c all
sudo pacman -Syyu
pacman -Qs dbus

if still missing

sudo pacman -S dbus-broker dbus-broker-units