A question regarding grub involving updates

[Bret Busby]

Hello.

In having just performed an upgrade (apt full-upgrade), which involved 
some grub updates/upgrades, the output involved the following.

"
Setting up kpartx (0.8.8-1ubuntu1.22.04.1) ...
Setting up grub-efi-amd64-bin (2.06-2ubuntu10) ...
Setting up kpartx-boot (0.8.8-1ubuntu1.22.04.1) ...
update-initramfs: deferring update (trigger activated)
Setting up gir1.2-webkit2-4.0:amd64 (2.38.2-0ubuntu0.22.04.2) ...
Setting up grub-efi-amd64-signed (1.182~22.04.1+2.06-2ubuntu10) ...
Trying to migrate /boot/efi into esp config
Installing grub to /boot/efi.
Installing for x86_64-efi platform.
grub-install: warning: EFI variables cannot be set on this system.
grub-install: warning: You will have to complete the GRUB setup manually.
Installation finished. No error reported.
Processing triggers for man-db (2.10.2-1) ...
Processing triggers for libc-bin (2.35-0ubuntu3.1) ...
Processing triggers for initramfs-tools (0.140ubuntu13) ...
update-initramfs: Generating /boot/initrd.img-5.15.0-53-generic
I: The initramfs will attempt to resume from /dev/sda6
I: (UUID=48b30053-cf4a-4d17-a988-dcc123b6750b)
I: Set the RESUME variable to override this.
"

So, I ran (well, it didn't, as shown)
"
root at bret-OptiPlex-9030-AIO:~# grub-update
grub-update: command not found
root at bret-OptiPlex-9030-AIO:~# man grub
No manual entry for grub
"

So, I searched in synaptic, for grub, to find how to update it, and 
found the package
update-grub
and lots of other grub associated packages.

But, what I am wondering, with also having found, in that search,

refind;
"
boot manager for EFI-based computers

A graphical boot manager for EFI- and UEFI-based computers, such as all
Intel-based Macs and recent (most 2011 and later) PCs. rEFInd presents a
boot menu showing all the EFI boot loaders on the EFI-accessible
partitions, and optionally BIOS-bootable partitions on Macs and BIOS boot
entries on UEFI PCs with CSMs. EFI-compatible OSes, including Linux,
provide boot loaders that rEFInd can detect and launch. rEFInd can launch
Linux EFI boot loaders such as ELILO, GRUB Legacy, GRUB 2, and 3.3.0 and
later kernels with EFI stub support. EFI filesystem drivers for ext2/3/4fs,
ReiserFS, Btrfs, NTFS, HFS+, and ISO-9660 enable rEFInd to read boot
loaders from these filesystems, too. rEFInd's ability to detect boot
loaders at runtime makes it very easy to use, particularly when paired with
Linux kernels that provide EFI stub support.
"

in the context of the output from the system upgrade, should I run 
update-grub (assuming that that would do what is required), or, should I 
be installing and using refind?

I believe that I have been using GRUB as the bootloader, for as long as 
I can remember having dual and multiple boot systems - there may have 
been something else, about 25 years ago, but I do not remember what.

Thank you in anticipation.

..
Bret Busby
Armadale
Western Australia
(UTC+0800)
.................