This one was a bit tricky.

In RHEL-based distributions like Rocky Linux 9, when GRUB_ENABLE_BLSCFG=true is set,
GRUB manages kernel boot entries using the Boot Loader Specification (BLS) instead of the traditional method
(where kernel options are directly written to /boot/grub2/grub.cfg).

Instead of reading the GRUB configuration file (/boot/grub2/grub.cfg),
GRUB directly loads configuration files from /boot/loader/entries/*.conf.
As a result, running grub2-mkconfig does not automatically update the configurations in /boot/loader/entries/.

By setting GRUB_ENABLE_BLSCFG=false, GRUB reverts to the traditional method
and directly edits and manages /boot/grub2/grub.cfg.