Once Ubuntu 18.04 is installed, I got stuck after the graphical login.
It appears this is a known bug (Password accepted but login fails (blank purple screen and mouse pointer only)), and people have already brought a workaround on AskUbuntu: Ubuntu 18.04 and nVidia. Stuck after boot.
So for short:
- Edit your Grub linux line to add
nouveau.modeset=0(you’ll be able to correctly log in)
- Then install proprietary drivers
TODO: find a way to make this usable with FLOSS drivers (called nouveau)