This could be the reason for your problem, although at a quick internet search this could be really only a “warning” not affecting the functionality.
Give a look at this one in our forum and see if anything changes:
Also, update your system fully (I see an old kernel, so probably this is a new install) with a:
garuda-update
Finally, on the Arch side, you could give a look at this:
https://wiki.archlinux.org/title/GRUB#Arch_not_found_from_other_OS