As another data point, my son was 5 when the lockdowns hit and missed the end of his kindergarten year and the entirety of first grade. He's doing fine.

My daughter was 18 months and went back to preschool at age three. She's also doing fine.

In fact I don't know any of their peer group who I would consider to be "having a terrible time adjusting to school and normal social interaction" which could be directly tied to Covid. There were some kids who had already been identified as having developmental challenges, and that hasn't changed.