Also, there is a possibility that US government agencies will close, and long-term US bonds are solid

The possibility of a government shutdown due to a US budget run out (9/30) has increased. The spending bill must pass by the end of September, but the Republican Conservative Hardline Freedom Caucus (Freedom Caucus) is demanding less spending than when the Biden-McCarthy agreement was reached in May, so an agreement is difficult.

As long as there is a high possibility that the government will shut down, it is impossible to short sell US bonds. You can also check past cases. At the time of government shutdowns in 1995-96 and 2018-19, conflicts over budgets stimulated demand for safe assets, and the exchange rate of US bonds rose. It is unlikely that long-term interest rates in the US will rise (price fall) in September.