The classic ‘risk free’ asset is US Treasurys, the US has never defaulted on its debt. Any yield above the risk free rate has implied risk, Brazilian bonds yield 13% because Brazil has defaulted on its debt several times. Brazilian bonds are at least an order of magnitude riskier than US Treasurys, and probably more than that.

FTX was paying well above the risk free rate (currently 3.25-3.5%, it’s been climbing since January 2022), implying they were taking risk to earn the yield they were paying.