Under GNOME, if you open the control center, go to “Universal Access”, select “Cursor Size” and then try and make the cursor the maximum size, the whole UI reproducibly hangs a moment later.
Logging in over ssh, I can see that the nvidia irq process is using 100% CPU. Also the system gets rather hot.
Upon reboot, when you try and log in again, the system hangs right away, presumably because it is trying to restore the huge cursor size. This means you’re effectively locked out of your user account.
Reproduced on Endless and on Fedora 30, running nvidia driver version 418.xx and 430.34.