My sister-in-law is a middle school counselor at a large midwest US public school system and her stories about kids dealing with the pandemic are heartbreaking, the mental health support system in some US schools is completely falling apart due to the workload.
She's never seen a mental health crisis on this scale in schools in her entire career. She remarks that kids really weren't able to learn much during the pandemic due to remote learning and in many cases are now playing catch-up to get back on track. The school system she works for basically didn't hold anyone back for a year because they had no real way of knowing who progressed as her school district cancelled standardized testing.
Anyone who believes that the pandemic wasn't a serious setback for many kids developmentally is woefully out of touch with reality.