Doesn't create submenu in Fedora 38

[lilin]

I installed grub-btrfs v4.12. changed all the necessary configurations to make it run properly on fedora, and it does run, even the daemon. However, this submenu doesn't show up.

This is very strange because

1. the snapshots are found when running grub2-mkconfig:

### BEGIN /etc/grub.d/41_snapshots-btrfs ###
Detecting snapshots ...
Found snapshot: 2023-09-09 18:55:35 | fedora_root/.snapshots/5/snapshot | single | N/A |
Found snapshot: 2023-09-09 17:53:15 | fedora_root/.snapshots/4/snapshot | single | N/A |
Found snapshot: 2023-09-09 17:44:56 | fedora_root/.snapshots/3/snapshot | single | N/A |
Found snapshot: 2023-09-09 17:15:25 | fedora_root/.snapshots/2/snapshot | single | N/A |
Found snapshot: 2023-09-09 17:14:55 | fedora_root/.snapshots/1/snapshot | single | N/A |
Found 5 snapshot(s)
submenu 'Fedora Linux snapshots' {
    configfile "${prefix}/grub-btrfs.cfg"
}

WARNING: '/sbin/grub2-mkconfig' needs to run at least once to generate the snapshots (sub)menu entry in grub the main menu. After that this script can run alone to generate the snapshot entries.

Unmount /tmp/grub-btrfs.dO7ePj4odn .. Success
### END /etc/grub.d/41_snapshots-btrfs ###
done

2. I changed the relevant configuration in /etc/default/grub:
   GRUB_DISABLE_SUBMENU=false

I also tried setting the place for the grub-btrfs.cfg file to either /boot/grub2 or /boot/efi/EFI/fedora, but either way the result doesn't change, i.e., grub2-mkconfig runs successfully, finding the snapshots, and even showing the submenu entry, but grub not showing it at boot.

[lilin]

In fedora when running grub2-mkconfig it is not sufficient to run the command alone, but one must specify also the location of the file with -o /boot/grub2/grub.cfg.