SSRS Web Service URL Unauthorized

I have installed SSRS on a 2019 SQL Server Instance, with both located on the F-drive of the same DEV machine.

As you can see, the Web Portal URL works:

But the Web Service URL doesn't, and logs the following error:

Also, when I try to connect to the Report Server in SSMS, it throws the following error:

I have been banging my head against the wall for four days, and am just flabbergasted there haven't been more posts (Google, Stackoverflow, here, anywhere!) from people experiencing this issue. The only thing I've read that strikes me as potentially at the root of my problem, suggests that the issue stems from the fact that I didn't install Report Server on the C-drive, and therefore the service won't start because it doesn't have write-access on the SSRS folders. Which seems very likely, because of the fact that an "unauthorized access" error is being thrown.

The article suggests to either:

A. Copy permissions from the C-drive and reinstall Report Server (ughhhh! last resort!)

B. Try to assign permissions on the pertinent F-drive folders, to the SQLServerReportingServices account. The only problem with that is, that specific account isn't listed, and I don't know what group the account (Virtual Service Account) belongs to.

Any ideas suggestions greatly appreciated!

Thanks!