Could you please copy and paste the full output of this command:
eos-update --yay
Perhaps just a terminology hurdle, but yay isn’t responsible for downloading “mirrors”. Updating your mirrors though is a good idea if having issues. Run these two commands (referenced from here) :
reflector --protocol https --verbose --latest 25 --sort rate --save /etc/pacman.d/mirrorlist
eos-rankmirrors --verbose