I see this sentiment a lot, they are not equivalent. The US must reduce spending, if it wants to protect the dollar. Tax increases may also help.
The relationship between tax rates, GDP, government revenue, the market value of new US debt, and the value of the dollar, is complicated and depends on uncertain estimates and models of the economy. Increasing taxes can reduce GDP, which needs to increase to outgrow the debt, there is an optimal tax rate, more doesn't always help. Decreasing spending is a more straightforward relationship, no new debt, no new dollars.