While it's true that the increase in interest rates is having some effect at the margins, a fundamental problem with the OP's thesis is that there's no _reduction_ in interest rates that creates the peak in 2022. That makes it hard for me to believe that interest rates are the only cause here.

Another, more correlated hypothesis for what caused the 2022 peak is that it's related to a combination of pandemic economic stimulus and pandemic-related changes in demand for software engineers.