So after some trial and error I settled on installing the nvidia drivers via the ppa:
sudo add-apt-repository ppa:graphics-drivers/ppa sudo apt update sudo apt install nvidia-driver-410
410 is the current live branch on the website: https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa and I'm also running an RTX 2080 so its the only version that supports my GPU.
The install completed successfully, and then I rebooted. I reboot to runlevel 3 because I saw that this is the right thing to do when installing graphics drivers. Then to start x:
sudo init 5
Now X starts, the screen lights up and the login window appears. I put my password in – then the screen goes dark.
Any ideas on what I should do to be able to fully log into X?