Adding nvidia_drm.modeset=1 kernel parameter seems to have fixed it for me, as someone mentioned in the nVidia forum thread. Haven’t seen the top third of my screen flicker since I rebooted with it set.
Setting kernel parameter how-to
In /etc/default/grub add nvidia_drm.modeset=1 to the GRUB_CMDLINE_LINUX_DEFAULT line, like so (your line might look different, just add it in the quotes):
GRUB_CMDLINE_LINUX_DEFAULT="quiet nvidia_drm.modeset=1 udev.log_priority=3"
and run
sudo update-grub
Reboot.