I’ve been debating whether to mention the easiest way to hide Grub boot messages: sudo pacman -R grub
and replace the whole thing with systemd-boot or rEFInd…
Well - here is a short form of the answer. Modern (ie: most current) Linux systems can be directly booted from UEFI. Grub is a boot system (called from UEFI) that manages loading things into place before starting them. It also can create menus, pass parameters and run an os-prober to determine what else is present that is bootable.
rEFInd is an alternative to grub that also searches out all bootable items and provides a menu for selection - then direct boots your choice. Systemd-boot (formerly gummiboot) is a simpler alternative that also direct boots using the systemd framework already in place. They are all different ways to end up in the same place, with different displays in the course of their operation.
That’s about as simple as I can make it at this time of day!
Can confirm this. I was enthusiastically using and recommending grub customizer until it no longer worked, not saving some settings, incorrectly setting other, and the menu not being what i’ve set it to be. Pretty buggy. I said, no matter I will go manual. Now that’s where things got even worse. It’s a pain to go back to normal grub after customizer.