The error message in your log shows that you have the grub package, which is the deprecated GRUB 1.x, installed, but have not configured it.
You should purge the grub package and instead install the grub-pc package, which is the supported GRUB2.
sudo apt install --purge grub-pc grub-
The error message in your log shows that you have the grub package, which is the deprecated GRUB 1.x, installed, but have not configured it.
You should purge the grub package and instead install the grub-pc package, which is the supported GRUB2.
sudo apt install --purge grub-pc grub-