I was in my phone before...
Well, allegedly from cran, you should be able to install dplyr, which points out as an error in some of your posts, but accordingly to cran, it should be able to be installed, but maybe fromcran some dependencies like rlang will require higher version.
I am not a fan of being super-updated (actually, I am against), but your R version is quite old. You should install a newer one, but as I remember from my experience with MAC, it may be an issue