I am not certain if this is Ubuntu specific or elementary OS specific.
On the lock screen, I do not have the capability to change my brightness using the dedicated keys on my keyboard.
It turned problematic when I had turned my brightness all the way down, when leaving the desk, and returned to a screen that had turned off (lock computer when away for x minutes), and effectively rendered nothing upon 'wake' because the brightness was set to 0 before I left the desk.
I could not turn it back on. Luckily, entering the password, hitting Enter and then changing the brightness rescued me -- but that is not an ideal solution.
I'm currently using nvidia drivers installed via
sudo ubuntu-drivers autoinstall