Hi, and welcome!
For future reference, please see the FAQ: What's a reproducible example (`reprex`) and how do I do one? Using a reprex, complete with representative data will attract quicker and more answers.
Do you see the following from a terminal window:
$ 529: ls -l /Library/Frameworks/R.framework/Versions/3.6/Resources/lib/ | grep libc.*
-rwxrwxr-x 1 root admin 825K Dec 12 10:55 libc++.1.dylib*
-rwxrwxr-x 1 root admin 212K Dec 12 10:55 libc++abi.1.dylib*