Fortunately for DS1, at 9 he'd just been diagnosed with his SENs shortly before the lockdowns.
For DS2 who was 7, it's been so much harder to get his SENs taken seriously, get through waiting lists and reach the point of diagnosis. It has cost him years of targeted interventions. He was just a bit delayed coz covid innit, they're all a bit delayed... except with a ND sibling, and not really catching up to normal expectations despite a switched on parent who works with young people, it is more likely than average that he is ND too.
His cohort lost out on the transition to juniors. They walked out of school as little infants, and by the time normal socialising was legal, they lost that transition to forming more specific friendships and were expected to pick up as juniors. Some children were allowed access to school and contact with their age group, and others were prohibited from age appropriate socialising. As a general cohort, the social skills of that year group are very difficult. They are both immature and childish, but simultaneously excessively exposed to the world online. It's a bad combination, but there is widespread reporting locally that y8 is particularly difficult for their age compared to usual and it is likely that that loss of social transition added to loss of support and resources in education / SEN provision is a part of that pattern. DS comes home moaning about his class; I have a colleague who has taught him/them and agrees that they are very challenging compared to the general issues of education at present.
It's not just Covid lockdown, there's the related side effects on public services, the state of the economy, and increasingly digital childhoods, but the lockdowns both directly and the cost of keeping the economy afloat have had major impacts on the quality of childhood across the cohort. There hasn't been the resourcing to fix the damage done in 2020-21 and disentangle it from other issues.
I have found from working with young people that it hit different age groups in different ways depending on their development stage and transition points. DS1 being y4-5 was at a more stable stage and less impacted. I'm finding the "covid toddlers" very socially young for their age and their parents are very insecure and anxious; likely a legacy of being deprived from toddler groups, forming mum-friendships and lack of access to services such as HVs. They were pushed into support online rather than in person, and we're having more trust issues and parents believing in their child's age-appropriate development and maturity than usual. There has also been the loss of early interventions where public services never caught up on delays in care.