Driving its value down a little, without losing control in a run, is the best way to delay the inevitable run to get out as for the next year or so, that lower value dollar will boost US exports, reduce imports and the trade imbalances to give "short sighted" foreign investors confidence that holding dollars is secure.
Who are these "short sighted" investors, and how are they influential enough to make a difference? Not major dollar holders like China, Japan, Europe and the Arab states, all of whom have been publicly furious at the pro-inflationary steps being taken. They're seeing billions in assets wiped out by these policies, right now, and are openly unhappy with it and looking for ways to avoid absorbing even more dollars (as you so frequently remind us).
Meanwhile, exports and trade imbalances are not being affected, since China is pointedly refusing to play along and Europe is suffering a banking crisis. What's happening is that the asset sheets of dollar holders are being degraded, and US entities are accumulating all the attractive foreign assets they can get their hands on with the cheap money. This is not a confidence game to boost demand for the dollar - it has exactly the opposite effect, by design. There is no need to boost demand for dollars, given the rock-bottom rates we're currently paying to borrow.
Rather, this is a concerted effort to leverage that demand in order to devalue American debts and accumulate foreign assets. It works exactly because a run on the dollar would cost places like China, Japan and Europe trillions and so destabilize their economies, while eliminating the US national debt. A run on the dollar would wipe out a trillion or more in Chinese assets - that's like 25% of GDP, a nightmare scenario for the CCP. It would be as if all those years of trade surpluses never happened, and China had just shipped us goods for free instead. That's very bad for China, and very good for the USA.
Just as the dollar is the least-bad investment in hard times, the US would be the least-injured party in a run on the dollar. And so, perhaps counterintuitively for some, everyone else fears such an outcome more than the USA does. That's why it won't occur, and why the USA can get away with inflationary policies. It's like the old saw: "If you owe the bank $100, that's your problem. If you owe the bank $100 million, that's the bank's problem."
Significantly strengthening the dollar would make even the dumbest investors realize that the US's debts were already unpayable.
Doesn't compute - US debts are denominated almost entirely in nominal (not inflation-adjusted) dollars. They can't be "unpayable" because the US can just print whatever amount of dollars is required (thereby weakening the currency appropriately). Deflation makes people happier to hold and accumulate dollar-denominated debt. Inflation works the other way. You might as well be arguing that up is down here.
Now they can hope that a controlled weakening plus some recovered growth will let them get their investment back.
Growth doesn't compensate debt holders for depreciated dollar holdings. They just get paid in the depreciated dollars. The beneficiaries of the growth are others - which is, again, exactly the point here: we're running inflationary policies in order to soak holders of our debt while improving our own position.
So, once again, you've tried to have it both ways in your rhetoric and ended up in a self-contradictory morass. I suggest you stop digging the hole deeper, and instead pick a consistent viewpoint and stick with it. While this will prevent you from claiming vindication irrespective of what actually transpires, it will have the advantage of giving people a reason to listen to you.