Interesting, so that fails only with the new .iso images, both with installed GRUB and Super Grub 2?
I just tried (in GRUB using very similar commands) :
garuda-sway-linux-zen-220909.iso works
garuda-sway-linux-zen-230319.iso does not boot
garuda-dr460nized-linux-zen-230319.iso does not boot
but mine fail to boot even earlier, hang on a black screen just after "Starting systemd-udev" or something like that. 
edit: can you try with the commands I'm using? I think that 1) I have a different problem 2) maybe export rootuuid makes a difference, but I forgot why I put it there, I have to RTFM.