Laptop is a Dell XPS with OLED screen and nvidia 1650 currently on nvidia driver version 440.
The mouse cursor will flicker when an external monitor is plugged in.
These questions generally go unanswered
-Mouse flickering, 2 displays, 18.04
-Laptop display flickers when external display is connected [Ubuntu 18.04]
Is this out of our hands and very much an Nvidia driver issue?
The best solution seems to be not to use Wayland and lower built in display to 1080p.
Connect monitor
Lower built in display to 1920x1080
Set scaling to 100% on both
Tested on driver nvidia-440
When disconnecting the monitor the resolution will set the built in display back to 4k so you shouldn't notice any difference between docked/undocked, except for the obvious loss of quality when watching videos etc (while docked).
I fixed my version of this issue by commenting out the following line from /etc/X11/xorg.conf
# Option "SWCursor" "true"
After a reboot my mouse flickering went away, and some other visual bugs as well!
