Children born during the pandemic are not yet in school. This research makes little sense, measuring cognitive differences of 2 year olds is highly unlikely to be meaningful.
"measuring cognitive differences of 2 year olds is highly unlikely to be meaningful."
Do you have expert knowledge, or at least experience with lots of different 2 year olds, to make such a statement?
Because I got some experience and I can tell you, there are great differences to be meassured for sure.
Whether they meassured correctly, I do not know, but I can imagine that the chaos of the pandemic was not always helpful for child developement. Just alone the social contacts are vital for developing - and they were greatly reduced (often replaced with screen time) compared to normal 2 year olds.