That's the point. The government isn't on the hook for wealth. They are on the hook for dollars. And dollars, to the US government, are "free".
>Doing that is impossible, though. Reducing the value of a dollar means that you'll need even more dollars to repay that debt than you would have needed otherwise. There is no net gain here.
The amount of debt doesn't go up if the value of the dollar goes down.
The interest rate goes up almost instantly when the government prints money. That's not exactly equivalent to increasing the debt value, but it's more than enough to make the "just inflate it away" strategy fail 100% of the times some country tries it.
Same with US dollars. Half of them might be held by non-US persons. Another quarter by US population. Printing dollars is a wealth redistribution excersice and a very effective one.
The government cannot create wealth "for free". It can print more dollars, but in doing so it makes each dollar worth less. No wealth is actually gained.
> there are knock on effects of creating enough dollars to zero out the debt
Doing that is impossible, though. Reducing the value of a dollar means that you'll need even more dollars to repay that debt than you would have needed otherwise. There is no net gain here.