When you control the mint, it's basically the same thing. Doubly so when its the USD and the rest of the world has exactly the same problem you do, so you hardly need to worry about the depreciation vs other currencies.

(Even if you hardly needed to before just by sheer size.)

That assumption is incorrect for sovereign currencies issuers (like the US, UK, Japan). They would just issue bonds, which is not at all like you or I taking out a loan.