Amigos!
First a shout out and thanks to Alexjp, whose kung-fu saved the day, and BluishHumility for having taken the time to learn me to the fix. https://forum.garudalinux.org/t/performance-optimized-repositories-cachyos-aur/23773
- Commented-out the cachyos repos in /etc/pacman.conf
- Did as root a 'pacman -Syyuu'.
- Migrated previous configuration from /etc/mkinitcpio.conf into /etc/mkinitcpio.conf.pacnew and then 'mv /etc/mkinitcpio.conf.pacnew /etc/mkinitcpio.conf'
- Found the "vmlinuz" linux kernel for the 6.0.2.linux-zen in /lib/modules/6.0.2.linux-zen/
- copied to /boot the 'vmlinuz' to 'vmlinuz-linux-zen' as per the grub.cfg .
- Restored the linux-zen.preset to /etc/mkinitcpio.d/
- Built the missing cpio initramfs archives in /boot by doing a 'mkinitcpio -v -P'
- Did a 'grub-install', double checked the /boot/grub/grub.cfg entry I intended to boot from, ensuring the files made by step #3 above were named exactly the same.
- 'update-grub'
Then a 'sync ; shutdown -r now', and it was smooth sailing from there... Don't worry: I then did a garuda-update to re-Garudaize everything after reboot. I chose to do the 'pacman -Syyuu' instead of garuda-update because garuda-update would oddly fail on the mkinitcpio portion. In regressing to the ARCH version, my linux-zen.preset suddenly reappeared... Odd...