Changing GRUB keymap has been discussed in this thread:
Hello new to Garuda Linux and first just want to say thanks for making the distro. I have been enjoying my time on it quite a bit. I really like the encrypted install script for Garuda as well that it uses full encryption thereby hiding your initramfs and kernel. I have installed my /boot/efi partiiton to a usb disk and my nvme drive is just two partitions (swap and root) which are of course both encrypted. This is good to prevent the 'evil maid attack', so if I leave my laptop somewhere I c…
And you find this from the Arch wiki
What I meant by automation during the installation process is that GRUB keymap would be set automatically to the one that is selected … now it seems to default to US layout, even one selects another one during the installation.