The collapse would be two fold.Everyone's missing the point. The issue isn't 'would destroying the dam cripple the PRC, doing enough damage to cause it to lose stability/the Mandate of Heaven/what Liu Cixin described as 'the foundation of human civilization is to have things to eat'. Nor is it 'could the dam be destroyed'. It almost certainly would and there are almost certainly multiple plans of varying degrees of practicality and sanity in folders in the pentagon or some technothriller writer's drafts for how it could. Rather, the point is that the PRC would launch a retaliation strike and given that they've got nuclear ICBMs and very likely software backdoor killswitches in all our civilian infrastructure, they could also destroy us as well before they collapsed. This leaves the possibility of false-flagging the dam's destruction as a natural disaster or some kind of jihadist attacker upset by the uighur genocide for use of a standard Alphabet Agency proxy, but that doesn't take into account the possibility that the PRC might launch a nuclear retaliation strike anyway, given that they were already losing and couldn't prove it wasn't some CIA scheme, or that given their track record over the past few decades, I have minimal confidence that the Alphabet Agencies could pull it off at all and none that they could successfully hide their presence.
Destroy the civilian structure we destroy everything of thiers.
But the Dam definitely is a target for sabotage.
Most likely going to burst before that thoigh