I think that (1) we're shooting anything that looks like a Chinese balloon (2) We're accusing Russia of crimes against humanity while also threatening to leak our intelligence that China is thinking of providing them lethal aid (3) we're quadrupling our troops-on-ground in Taiwan (from a "tiny handful" to a "small handful" but still) (4) we're letting it be known that the lab leak hypothesis is gaining ground (5) we're stationing nuclear bombers in northern Australia is the United States informing China that there's a whole lot of shit that can be unwound, a step at a time, clear back to Tienamen Square. That "U2 taking a selfie with a Chinese surveillance balloon" thing is the sort of provocation that the talking heads will miss but the Chinese won't. Because while in the US the U-2 is mostly known as "that thing that Gary Powers got shot down in" it's basically the goad we prodded China the hardest with.