Can we explain why the external and fiscal deficits do not lead to a depreciation of the dollar or to a rise in dollar interest rates?

The US external deficit is now increasing rapidly since US fiscal policy is highly expansionary in a situation of full employment. So we are seeing the famous "twin deficits" (fiscal and external deficits) but, unlike what we have seen in the past, this time they are being financed by central banks since global foreign exchange reserves are decreasing. The twin deficits, which are getting worse, must be financed by private investors in the rest of the world, without the support from central banks, and this ought to lead to a depreciation of the dollar or to a rise in US interest rates. However, we see neither of these: the growing US twin deficits are easily financed. This is probably explained by investor concern about other regions, which makes it attractive to invest in the United States. As a result of the decline in growth in China, the euro zone and Japan, and due to the zero interest rates in the euro zone and Japan, investors prefer accumulating dollar-denominated assets, which finances the US twin deficits. But can this be a long-term equilibrium?