Grub 2:2.06.r322.gd9b4638c5-1 won't boot and goes straight to the BIOS after update

Hello guys.

I am so frustrated having my system go down from updates. this is like the 3rd major hiccup for me in last 4 months.

Anyway I know there is documenation to fix the issues but when the documenation doesn’t line up with what i am seeing. it gets confusing fast.
I am following this grub fix post. and doing these instructions to the letter. but things look different and i am just stuck. I can’t seem to google my way out of it.
Articles i am following

and
https://discovery.endeavouros.com/system-rescue/arch-chroot-for-efi-uefi-systems/2021/03/

So i boot from EndeavorOS ISO the latest version. I fdisk -l and mount my RFS to /mnt. however lt shows the following 4 directories on my nvme.
@ @cache @home @log

when i cd to @ i can see my RFS.

So i guess i have to sudo arch-chroot /mnt/@ cause thats where the /proc and /dev directories are etc.

Which also means i need to mount my 512M EFI system to /mnt/@/boot/efi

So i do this and then type sudo arch-chroot /mnt/@

Which then gives me a warning
Warning: /mnt/@ is not a mountpoint. this may have undesirable side effects

Then i try running grub-install and i get an error.

grub-install:error: cannot find device for /boot/grub (is /dev mounted?).

I researched on google as much as i can remounted some paths. grub-install just won’t run without error.

What is the proper documentation to follow that will restore my grub and get my system working agian?

Thanks.