Jordan_U , 4 months ago

This should get you back to defaults:

sudo cp /usr/share/grub/default/grub /etc/default/grub && sudo update-grub

At some point you definitely did accidentally write to /etc/default/grub when you meant to write to /boot/grub/grub.cfg.

There’s no shame in that; Grub’s configuration process is very confusing and counter-intuitive.

Everybody who has used Linux long enough has stories of breaking their systems in sillier ways, and this didn’t even really break your system 🙂.