Jason,

I disagree with your characterization of the risk free rate. In essence, the only thing genuinely missing from the original RFR name is the underlying extension of "risk free rate for a given currency". Frankly if the short-term Bill/Bond of the appropriate time metric were to go into default, then the currency that you are trading in also does not have the same given value that you are trading in. If a T-bill/bond goes into default, then the dollar also follows a devaluation which would make it move in tandem with these rates... as such relative to the dollar, the rates would be the same given the dollar and are thus 'risk free'.

Considering every investment calculation has an underlying assumption of currency, then the rate corresponding is 'risk free' relative to that currency.