Have you tried using / instead of \ ? R uses the latter as an escape character so cannot read normal Windows paths correctly.
Warning: I have never used Windows for R, just macOS and linux.
BTW, library(tidyverse) will load dplyr, ggplot2, lubridate, and tidyr (along with forcats, purrr, stringr, readr, tibble) so there is no reason for library(dplyr), library(ggplots2)... .
Also, the readxl package has no external dependencies, unlike xlsx which needs Java.
If you are using your own computer, you only need to install packages once. They should appear in your User Library.