Thank you for the help. However, it did not solve the problem.
In addition to this, I changed my "PATH" variable to include the RTools installation:
Sys.getenv("PATH")
[1] "C:\Program Files\R\R-4.0.0\bin\x64;C:\Program Files\Python38\;C:\Program Files\Python38\Scripts\;C:\Python27\;C:\Python27\Scripts;C:\RTools40\;C:\RTools40\mignw64\bin\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files\MiKTeX 2.9\miktex\bin\x64\;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\nodejs\;C:\ProgramData\chocolatey\bin"
I am still getting the same error: "WARNING: Rtools is required"