They’ll be fine. They just need to reduce their population by 33%, before May 1. They’ve done it before.
China is already in the middle of a population collapse. They don’t need to manufacturers one.
As for an economic collapse, China isn’t like other countries. They will hold it together long after Western countries would have been long gone. The CCP has such tight control on media that 90% of the people would have no idea a collapse was happening and the other 10% would keep their mouth shut.