improper handling of EFI/grub instal…” : Questions : Ubuntu

I just installed Ubuntu 23.10 to replace my LMDE 6. I choose to manually partition my hard disk because I want to preserve files under /home.

The problem is, after installation, Ubuntu failed to boot into login screen and just show me the “grub” command line prompt. By some research, I found that it is because the machine choose to boot into the old debian installation, which of course does not exist any
more.

Since I did not choose to install Ubuntu while still keep my old operating system, I don’t think it is reasonable for the installer to NOT wipe out boot loader of the existing system. Would it be nice to just force formatting of the EFI partition, in such situation?