I think the lockdowns are because they were able to successfully beat the virus and contain it to mostly Wuhan last time with drastic measures, and even in Wuhan it was gone in 6 weeks.

There were no countrywide large surges till now, so they're still clinging on to it, a bit like Australia, NZ etc. with Omicron.

>Assuming a lab leak they may well be aware of these effects already from previous research and therefore enforce zero-covid to avoid it because it's riskier than we currently understand

What previous research is needed when in the past few years the virus has been studied in real life scenarios with massive sample sizes across almost all ethnicities, age groups, comorbidities etc. The dangers have been well documented by a huge number of real life experiences and studies in the west and else where. Every bit of the RNA code has been studied extensively for it's effects. So I think the scenario of "bioweapon designed so that everyone wh had it drops dead in 7 years" is super unlikely if not impossible.