That's not true at all. The "risk free rate" is a theoretical concept that represents the rate of return that you can get on capital without taking any risk.

That's not true at all. The "risk free rate" is a theoretical concept that represents the rate of return that you can get on capital without taking any risk. No bond alone is the risk free rate. Neither is the reverse repo rate or the rate of a money market. All of these are proxies.