System froze during an update

[mayhem]

along with what xircon suggests try the first solution in the linked reply

Kernel panic after broken update, pacman not working inside chroot

browsing endeavour, arch and nvidia forums and reddit threads all day has yielded 2 possible solutions to this: 1: its a systemd issue. solved by executing sudo touch /etc/systemd/do-not-udevadm-trigger-on-update 2: its an nvidia driver issue with the 550 beta series drivers. downgrading to 545 and 535 is suggested.

and in case pacman doesn’t work you’ll need to use a live iso to re-install packages