"However, if interest rate cuts begin, the SBE will likely not sustain its current levels of buybacks."
It could become a risky play for them. Firstly, they'd need to hold longer-dated U.S. T-bills.
This likely reduces their interest earnings as U.S. 10Y T-notes are ~4.5% vs 5.4% U.S. 1M T-bills. This implies a -16.67% opportunity cost without accounting for hedging costs yet. Also, hedging for short-dated T-bills is not impactful due to their shorter duration. They'd also need to consider and 'guess' when the rate cuts might happen.
Hence, I think the risks, costs, and complexities of hedging outweigh their current strategy to simply farm T-bills.