Hello and welcome,
It appears this section is missing.
So it is unclear what has been attempted so far.
First, I know it may sound a bit silly .. but is the time set correctly?
Then I would probably sort mirrors, then clear cache and signatures, repopulate, and force the install of the keyring first;
sudo cachyos-rate-mirrors
sudo rm -r /etc/pacman.d/gnupg/
sudo pacman-key --init
sudo pacman-key --populate
sudo pacman -Scc
sudo rm -r /var/lib/pacman/sync
sudo pacman -Syy archlinux-keyring cachyos-keyring
It may be helpful to include the full output of;
sudo pacman -Syu