Their vaccine is not very effective against omicron, and they have far less hospital beds per capita than the west. So a 'flatten the curve' strategy will cause a lot more deads than it has in Europe and the USA.
I don't think the number of deaths is the problem now but the speed at which they occur. If we assume about 0.2% death rate for China on average that would almost be 3 Million. Of those 1.5 Million would occur in 4 weeks (assuming speed is similar to Hong Kong and lower medical capacity). That's 50000 dead per day on average. Especially in the first half it's scary because the number just keep on rising to the sky with a peak of 100000 per day (or more? we don't know until they fall again).
The difference in effort between keeping that kind of curve flat and ZeroCovid is small. I would even assume that ZeroCovid is easier than flattening the curve. While ZeroCovid is not an exit strategy in some areas it works better while waiting for an effective vaccine or some other exit strategy. So presumably that's what they do right now.
