---

and then you can fully refresh your mirrors and update your keyrings:
sudo cachyos-rate-mirrors
sudo pacman -Syyu archlinux-keyring cachyos-keyring --needed
sudo pacman-key --populate archlinux cachyos
if even this fails, there are more “robust” ways of resetting signatures being the following
sudo rm -rf /etc/pacman.d/gnupg
sudo pacman-key --init
sudo pacman-key --populate archlinux cachyos
sudo pacman -Syyu archlinux-keyring cachyos-keyring --needed
sudo pacman -Scc
clearing the cache with -Scc isnt needed but can be helpful.
let me know how it goes