A summary of my suspitions on a possible bug can be viewable on this post
The topic is about Garuda grub is not generating other Linux OSes CMDLINE parameters from their original installations configuration.
I am not sure (yet) if the issue is because of a bug in grub, Garuda modifications, or Fedora setup and configuration.
I assumed it was because of Fedora uses btrfs, as Garuda, while Garuda mods are focusing on a different btrfs layout model.
In the posted grub.cfg of user's garuda system, it seems there is a difference in
linux lines (of
os-probered Linuxes) between Primary entry and Advanced options for... entries.
The user had modified
/etc/grub.d/30_os-prober to explicitelly add Garuda CMDLINE grub parameters to ALL os-probed Linuxes.
Nevertheless, the primary entry does not include the added params.
As his original issue was, grub-mkconfig was not adding Fedora's parameters, which is still under investigation.