Problem with installing Rtools: cannot locate the file in PATH - r

Question

I'm trying to download the package "Seurat" in R, the package is installed and it's now in my list of packages.
** testing if installed package keeps a record of temporary installation path
* DONE (patchwork)
The downloaded source packages are in
‘C:\Users\parnian\AppData\Local\Temp\RtmpAVgSd8\downloaded_packages’
But when I try to call it (library(Seurat)) I get the following error:
> library(Seurat)
Error: package or namespace load failed for ‘Seurat’:
object ‘wrap_plots’ is not exported by 'namespace:patchwork'
I read the similar questions and manually installed "patchwork":
> install.packages("patchwork")
WARNING: Rtools is required to build R packages but is not currently installed. Please download and install the appropriate version of Rtools before proceeding:
https://cran.rstudio.com/bin/windows/Rtools/
Installing package into ‘C:/Users/parnian/Documents/R/win-library/4.0’
(as ‘lib’ is unspecified)
R also tells me to install Rtools whhich I have, but when I follow these commands:
> writeLines('PATH="${RTOOLS40_HOME}\\usr\\bin;${PATH}"', con = "~/.Renviron")
but when I want to verify that make can be found (Sys.which("make")), I get this:
> Sys.which("make")
make
""
Also the downloaded packages of Seurat are saved in a location that doesn't even exist in my computer! How is that possible?
How can I fix this? Is there something wrong with the address I write for the path?
Thank you