How to add permanent kernel parameter?

cat /etc/default/grub 
GRUB_TIMEOUT=3
GRUB_TIMEOUT_STYLE=menu
GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=nvidia_wmi_ec"

cat /etc/default/grub 
GRUB_TIMEOUT=3
GRUB_TIMEOUT_STYLE=menu
GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=nvidia_wmi_ec"

ujust regenerate-grub

ujust regenerate-grub

and

sudo grub2-mkconfig

sudo grub2-mkconfig

don't work.

How to add permanent kernel parameter? - Bazzite