Absolutely right. If all it costs China to completely destroy what America has built for itself after WWII is a trillion dollars (even less, since there are many more US assets in China that can be seized as compensation than there are Chinese assets in the US) then it's a great bargain.
So here is my take on why US may have wanted to shape the narrative that this virus not only originated from Wuhan but in addition that there was on top of that a willful coverup by the Chinese government. It also squares with Tom Cotton spinning conspiracy theories from the very beginning and Trump and Pompeo insistence at the G7 that the world adopt the "Wuhan virus" labeling...
It is an attempt to assign "blame" of this outbreak to China, ideally with China accepting the fault/blame but at least getting enough worldwide nations to agree with the consensus that this was entirely or predominant the 'fault' of the Chinese.
So if it was just that the virus originated in China then the level of blame would be limited, but if it could be shown, or if the narrative could be spun and the consensus could be reached, that on top of the virus originating in China the Chinese government also did some sort of coverup after finding out about this new virus etc then that makes it categorically different and paves the way for potentially assigning of "blame"/"guilt" and thus allowing the extraction of penalties, making China pay for it, reparations, and things of that nature.
This is why there was so much push about the whole "China lied, people died" and the "Chinese doctor whistleblower coverup allowed the virus to get out of control" narratives. Given what we now know about COVID, even if the doctor's message was amplified by the CCP it was likely already too late at that point, the virus was already out, they might have slowed it down in Wuhan, but it would have went international anyway, so functionally wouldn't in the end have made a difference and we would still end up where were are today, just the timeline may be pushed out by some weeks at the most.
But back to the whole T-Bill thing and how this is all interrelated... T-Bill is backed by nothing but trust of the US government. It is like a social network, or social contract, that just like any other fiat currency it goes by the "network effect" and is largely a consensus based "web of trust" sort of thing... essentially it has value if enough parties believe it has value...
So ordinarily without an event like COVID if USA just up and says hey China we are freezing your T-Bills then yes the value and trust of the US government printing machine would shatter. But, in an extraordinary circumstance like this pandemic, if the US can manage to shape enough public and national opinions worldwide to get a large consensus that China is somehow to "blame" for this outbreak and that China should "pay", and if most of the important players in the world actually got on board with such a consensus, then the US may actually get away with something like this with impunity, in that it could invalidate what it owes to China and there would not in fact be any negative impact to its dollar status...
Hence why I believe they made it such a point of contention to get the G7 to officially recognize this as the "Wuhan virus", to cement that step towards attribution, fault finding, and being able to apply such international consensus to pave the way for exactly what they are now discussing in the US senate to force China to pay by wiping out the debt US owed to China.