So I actually read that study. (Sorry.)
First off its conclusion is that shutdowns aren't worth it because they cause economic damage. This is not surprising as it is written by economists and political scientists: Jonas Herby, special advisor at Center for Political Studies, Lars Jonung, professor emeritus in economics and Steve H. Hanke, Professor of Applied Economics. Good people to evaluate economic fallout; terrible people to evaluate effectiveness of non-pharmaceutical interventions.
Second this is not a study. It is a "meta-study" which means it uses many other studies as its input. How did it select those studies? By looking at all the studies that looked at lockdown effectiveness then rejecting almost all of them. There were 117 studies in their pool and they rejected 83 of them for reasons like "used modeling" or "used time series approach." They even reject any study that looked at the effect of "well-timed shutdowns." By excluding all the studies showing well timed shutdowns, they are left with the studies of poorly or randomly timed shutdowns.
They were left with 34.
I looked at the first study they listed of the ones they looked at. Their summary of that study was "that shelter-in-place orders are - for the average duration - associated with 1% (insignificant) fewer deaths per capita." I looked up the study, and the study actually concluded that "a longer duration of a shelter-in-place order is associated with lower cases and deaths per capita from COVID-19."
Keep in mind that this is from a study they did NOT reject, even though it looked at well-timed shutdowns.
So sorry, not going to take this economic study seriously when it comes to medical results. It cherrypicked results, and then was not honest about the remaining studies they looked at.