Composing grub.cfg for direct booting of operating systems as ISO files

On an USB stick, FAT formatted as a single partition and labeled "FiveOS", I've put the following:
Code:antiX-23.1_x64-full.iso
debian-live-12.6.0-amd64-gnome.iso
EFI
BOOT
BOOTX64.CSV
BOOTX64.EFI
grub.cfg
grubx64.efi
mmx64.efiThe content of grub.cfg is:
Code:search.fs_label FiveOS root

rmmod tpm #remove TPM (Trusted Platform Module)

menuentry "Debian 12.6 Live System" {
iso_path="/debian-live-12.6.0-amd64-gnome.iso"
export iso_path
loopback loop $iso_path
set root=(loop)
set loopback="findiso=${iso_path}"
export loopback
linux /live/vmlinuz boot=live components splash raid=noautodetect "${loopback}"
initrd /live/initrd.img
}

menuentry "antiX 23.1 full" {
iso_path="/antiX-23.1_x64-full.iso"
export iso_path
loopback loop $iso_path
set root=(loop)
set loopback="findiso=${iso_path}"
export loopback
linux /antiX/vmlinuz1 boot=antiX splasht disable=lxF raid=noautodetect "${loopback}"
initrd /antiX/initrd.gz
}I can boot Debian but not antiX. It always ends up with an error like: cannot find antiX/linuxfs.

Any suggestions welcome.