https://iea.org.uk/publications/did-lockdowns-work-the-verdict-on-covid-restrictions/
COVID-19 lockdowns were “a global policy failure of gigantic proportions,” according to this peer-reviewed new academic study. The draconian policy failed to significantly reduce deaths while imposing substantial social, cultural, and economic costs.
https://econofact.org/how-effective-were-pandemic-lockdowns
The research based on a variety of models suggests that the adoption of lockdowns in the face of the initial COVID surge was effective in containing transmission and deaths, albeit at high economic and social costs
https://www.theguardian.com/society/2023/jun/05/revised-report-on-impact-of-covid-lockdowns-leaves-unanswered-questions
So, not exactly black and white, so it depends on what you define as a success.
*Really don't want to turn this into a COVID thread.