I determined a workaround for the issue of a white screen after upgrading to Ubuntu 20/Rv4. I had some help from Nvidia support in that I have to use some xrandr lines to bring resolution from 3840x2160 down to 1920x1080.
"That’s a bug/feature either the i915 or modesetting driver introduced. Previously, it would always auto-add virtual resolutions. That got changed at some time so it would only add those if the display supports exactly one resolution (like most notebook displays do). Unfortunately, your display supports two, 4k@60 and 4k@40."
My new MSI GPU laptop has some pretty powerful graphics, but RStudio isn't built to handle such resolution, at least not yet. Unless there is an update coming, I will have to run resolution reduction code before RStudio to avoid the "White Screen of death..."
Thoughts on how else to get around the extreme resolution issue?