Thanks Everyone for their suggestions. FIXED! Better outline what I did
- After posting, I saw this
GRUB downgrade
I explicitly downgraded grub as per instructions and rebooted. Got 2 minutes of loading (better than 12).
I then removed a property in /etc/default/grub. As I mentioned in original post, I reinstalled Garuda on a new partition, and did not need the old one anymore. So no need to probe for other OSs (why would you want anything else but Garuda Linux )? I had tried this before, but maybe still had not got all the grub updates when I did.
GRUB_DISABLE_OS_PROBER=true
- I then took mrvictory's advice
garuda-update
sudo grub-install
sudo grub-mkconfig -o /boot/grub/grub.cfg
There were more updates, and a futher message about grub being downgraded. Rebooted and back in speedy startup bliss.
Given rolling releases and mirror sites, maybe it just took a few days for all the updates to bubble through. Thanks all.