Unable to install packages after R update: unable to access index for repository: internet routines cannot be loaded

I had a similar issue. I recevied the following error on startup

Error in tools::startDynamicHelp() : internet routines cannot be loaded

After investigation, I found my antivirus software has quarantined R-4.0.0/modules/x64/internet.dll. Unfortunately, my antivirus settings are controlled by group policy so I can't disable them to claim a solution.

So, after 4 phone calls and multiple attempts at fixing this problem, my institutional IT department were today able to disable the antivirus block that was preventing R and R Studio from working.

Apparently, to avoid this in the future, I need to run new programs from a specific folder. So it was the antivirus after all, but I couldn't change the settings from my end as I have a work computer.