Regardless of when this change comes, I think you could and should try to move forward.
The reported errors
Installing for x86_64-efi platform.
grub-install: error: /boot/efi doesn't look like an EFI partition.
/usr/bin/grub-probe: error: cannot find a device for / (is /dev mounted?).
look a bit strange to me at the initial chrooting step (I would have expected them maybe when install the grub later on (which is not needed here), but I'm not a developer...).
In the next outputs provided when you try to chroot, please copy the entire command + output from the system, to have a clearer picture of what was executed successfully and what went wrong.
And also that "/boot/efi doesn't look like an EFI partition" is a bit wierd.
I'm not really sure what else we could try. I think you should make a step back and provide:
the disks set-up with the output of fdisk -l and lsblk -o name,type,fstype,size,uuid,mountpoint
Thank you. I was having the same problem ("mount: /new_root: can't find UUID...") and these steps worked for me.
The only issue I had was that the Windows entry was gone from the Grub menu but I had made a backup of the original grub.cfg and was able to correct the new grub.cfg manually.
@pla
By-the-way, I see that soon is getting closer...
This one below is a development daily build (or something like that, anyway nothing official), but I see for the first time mkinitcpio 31-1: https://iso.builds.garudalinux.org/iso/garuda/dr460nized/211202/garuda-dr460nized-linux-zen-211202.iso
If you want to give it just a try reinstalling and see if it works...
But I strongly suggest that you reinstall whenever there will be a new official release (also here, Soon™ )
Off
but your link is much better.