The key difference here @alonviten is that they don't necessarily need high CPI inflation in order to sustain this.

Do they even need to "inflate it away", or is kicking the can enough?

If they continue monetary inflation (e.g QE) whose new supply goes into assets (asset price inflation), they can create a new endless stream of money toward treasuries. Obviously, if your stock portfolio went up 3x, you will diversify a bit more into treasuries (as well as pay extra taxes)

As you can see, it worked pretty fine from 2010-2020 - https://fred.stlouisfed.org/series/GFDEBTN / https://fred.stlouisfed.org/series/GFDEGDQ188S. Debt-to-GDP increased from 80% to 100%, but total debt increased from $11T to $23T! (100%)