How did you install ruby there? One-click installer? If so then I am not sure
why you attempt to install rvm. I don't think that is necessary; back when I
used ruby on windows sometimes, the one-click installer worked.
Either way, this is probably not the ideal place for the above problem since
it does not seem to be related to ruby core (dev team).
RVM has not seen an update in 6 years either: https://rubygems.org/gems/rvm/
The ruby one click installer (for windows) is at version 2.7.1 so you don't
need rvm really.