Updating my own thread to be clear, I followed these specific steps from @cscs
Then when I run a sudo pacman -Syu I am still getting the error–
error: failed retrieving file 'linux-cachyos-lts-6.18.22-1-x86_64_v4.pkg.tar.zst' from us.cachyos.org : Maximum file size exceeded
error: failed retrieving file 'proton-cachyos-slr-1:10.0.20260408-1-x86_64.pkg.tar.zst' from us.cachyos.org : The requested URL returned error: 404
error: failed retrieving file 'linux-cachyos-lts-nvidia-open-6.18.22-1-x86_64_v4.pkg.tar.zst' from us.cachyos.org : Maximum file size exceeded
warning: too many errors from us.cachyos.org, skipping for the remainder of this transaction
error: failed retrieving file 'ttf-dejavu-2.37+18+g9b5d1b2f-8-any.pkg.tar.zst' from archlinux.cachyos.org : The requested URL returned error: 404
(255/255) checking keys in keyring [------------------------------------------------------------------] 100%
(255/255) checking package integrity [------------------------------------------------------------------] 100%
error: linux-cachyos-lts-headers: signature from "CachyOS <admin@cachyos.org>" is invalid
:: File /var/cache/pacman/pkg/linux-cachyos-lts-headers-6.18.22-1-x86_64_v4.pkg.tar.zst is corrupted (invalid or corrupted package (PGP signature)).
Do you want to delete it? [Y/n] y
error: failed to commit transaction (invalid or corrupted package)
Errors occurred, no packages were upgraded.