I also have this problem.
Differences for me:
I have a RTX 2080 and installed Nvidia's 410.78 driver manually.
Whenever I boot, I too get the black screen with a blinking cursor. I also have the ctrl+alt+F3, login and run startx
This brings me to the gnome desktop instead of the traditional Ubuntu desktop.
I am not really sure how to fix this issue.
I also have this problem.
Differences for me:
I have a RTX 2080 and installed Nvidia's 410.78 driver manually.
Whenever I boot, I too get the black screen with a blinking cursor. I also have the ctrl+alt+F3, login and run startx
This brings me to the gnome desktop instead of the traditional Ubuntu desktop.
I am not really sure how to fix this issue.