The suggestion for a garuda-update was mainly for “good hygene”, in case a new update was available and especially if a kernel update was available, which would trigger a dracut-rebuild (which could anyway be launched manually), since your error seems to be related to the initial ramdisk not being loaded, and that one is generated by dracut.
Here is a tutorial about chroot, which does manually what is done with the dedicated button in the live USB (grub installation excluded):
Further info here (but you don’t have to follow the Arch steps):
https://wiki.archlinux.org/title/Chroot