It was just for you to compare my pretty much unaltered file with what you have.
One thing I saw:
You have
GRUB_DISABLE_OS_PROBER=false
active
This means:
it is NOT disabled - it is enabled
read the explanatory comments above each option:
The following is the default setting.
# Uncomment this option to enable os-prober execution in the grub-mkconfig command
#GRUB_DISABLE_OS_PROBER=false
comment that option again if you are not dual booting
Research what install-grub does - nothing exiting.
Here is one thread with an example of what it does:
Totally broken system after December 2025 Stable Update - #82 by Nachlese
essentially this:
sudo cp /boot/efi/EFI/Manjaro/grubx64.efi /boot/efi/EFI/boot/bootx64.efi