I think you could buy long term treasuries at the currently high interest rates. When interest rate goes down, your treasury value goes up.
The problem with this is that UST's are being used as collateral (maybe not for the "real economy" but definitely financial assets), are also rehypothicated many times over and face liquidation risks in line with notional value of credit risks of the positions its backing.
Buying and holding long dated UST is like being leveraged long duration in the environment where interest rates are more sensitive to the credit risk of other assets in the system.