Looking at the videos sources. most of them point out that the actual act of social distancing and the like is effective, but its unclear whether more draconian rules actually change behavior. Most say that the timing (locking down early) may be more important than how severe the restrictions are.
https://onlinelibrary.wiley.com/doi/10.1111/eci.13484 - this one is making the point that lockdown *orders* aren't effective, not the actual act of locking down. They aren't questioning whether the act of locking down works, they are questioning whether lockdown orders actually change behavior.
https://www.medrxiv.org/content/10.1101/2020.06.11.20128520v1.full-text - this one similarly suggests that moderate as opposed to strict lockdowns might be as effective - though they really make the point that the actual act of social distancing, not the policies, saves lives.
https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(20)30208-X/fulltext -> states it didn't reduce cases but "full lockdowns...and reduced country vulnerability to biological threats...were significantly associated with increased patient recovery rates.
https://fee.org/articles/3-studies-that-show-lockdowns-are-ineffective-at-slowing-covid-19/ -> this is just an article that cites other sources that the video already cites.
https://www.bloomberg.com/graphics/2020-opinion-coronavirus-europe-lockdown-excess-deaths-recession/ - similarly, they say its more about timing than strict lockdowns. They also said "What’s not clear yet is how much economic benefit countries with relatively lax curbs really stand to gain, given the integrated and trade-driven nature of the European economy.", which is an interesting point.
Ignore New Zealand if you want, but they had cases and managed to keep those people quarantined and not let it spread like us. Looking at cases per 1m population: Canada: 762, Mexico: 2,211, USA: 2,315.