We're aligned, except, possibly for the graphics card (Intel HD Graphics 6000 1536 MB), which doesn't show.
R version 3.6.3 (2020-02-29)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS Catalina 10.15.3
Matrix products: default
attached base packages:
 stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
Again, there are two R3.6.3 versions, and I'm using the notarized package.
Installing the notarized version, if you installed the other, and using the RStudio Global options software graphics if your graphics device is different may help. Please report back and mark your answer as a solution, if joy ensues, or I'll see if I can get someone in the RStudio shop to look at the issue.