Why do you say the research is inconclusive?
The Wikipedia link showing support for lockdowns as you describe is https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7881715/ . Some quotes:
> Lockdowns are found to be the most significant NPIs in terms of variations to the Rt
> The results, which where published in July, paint quite a grim picture which unfortunately has been later confirmed: measures in place after the strict lockdown is lifted are not enough to avoid the overwhelming of the healthcare system.
> Early implementation of lockdowns has been found associated with large reduction of incidence.
> The results confirm the effectiveness of lockdowns and travel bans.
> Furthermore they suggest that partial lockdowns might be as effective as full lockdowns if implemented earlier.
Or, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8325386/ where Itay's red zone is closest to a full lockdown:
> the red zone policy was by far the most successful in reducing the rate of growth of new cases, hospitalizations in regular wards and ICUs.
> the red zone is an instrument that makes it possible to rapidly bring down cases and the speed of transmission of the virus and consequently both hospitalizations and deaths (being very correlated). However, it implies severe social and economic consequences due to forced economic activity suspensions and restrictions on the freedom of movement. Therefore, this choice can be considered as a tool of last resort in cases of dramatic spread of the epidemic or when the local health system is close to the collapse.
> There is a vast literature on the effects of nonpharmaceutical interventions (NPIs) of various measures on the speed of spread of COVID-19 ... Many studies have proven the effectiveness of these measures in reducing the spread of severe acute forms of COVID-19
You write "we don't implement prohibitions at the same level with smoking, drug use and junk food".
I'll again point out the guideline that lockdowns are meant as "short-term measures to reorganize, regroup, rebalance resources, and protect health workers who are exhausted."
With evidence that it works - experience in enacting a cordon sanitaire for smallpox, Ebola, and SARS outbreaks: https://en.wikipedia.org/wiki/Cordon_sanitaire_(medicine)
What sort of evidence is there that a short term intervention will help reduce deaths due to smoking, drug use and junk food?