We can look at the effect of anti-COVID measures by examining regions with small amounts of COVID but large amounts of anti-COVID measures like Australia and New Zealand. You can even compare between Australian states like Victoria that had 6 lockdowns and WA that had virtually none.
The result is that all cause mortality went down, largely due to elimination of respiratory viruses but also due to a slight decrease in car accidents. Suicide rates actually went down, not up and there was a uptick in self-reported mental illness and distress but that uptick was far smaller than the later uptick when COVID became widespread. The economy took a hit but a far smaller hit than countries that that let COVID rip.
The effects of lockdowns are real and measurable and they are bad but far, far less bad than COVID itself.