sudo pacman -Sy archlinux-keyring
sudo pacman-key --populate archlinux
sudo pacman-key --refresh-keys
one error you are possibly getting
installing<PKG-HERE> breaks dependency <PKG-HERE>
ERROR FIX FOR:
: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
error: failed to prepare transaction (could not satisfy dependencies)
:: nvidia: installing nvidia-utils (390.42-1) breaks dependency 'nvidia-utils=390.25'
sudo pacman -Syyuu --ignore nvidia-utils # How I upgrade sys argv[1] after ignore ignores upgrading that dependency if their new release breAKS AS DID NVIDIA HERE