It is impossible to see how being a child during coronavirus lockdowns will fit into history in 50 years time because we are all too much in the middle of it now and the ending is still unknown.
In some ways, I come relatively close to being an adult who was a child and then a young adult during coronavirus lockdowns. I had chronic undiagnosed health problems which resulted in a lot of isolation and then when diagnosed initially had to be treated with immunosuppressants, and so had to be very careful about infections. I also had a father on chemo, so as we say now 'extremely clinically vulnerable', and had to be careful not to bring infection to him.
For many years of my youth, my life was at best something like ''tier 2' and at worst something like lockdown.
I had a supportive family and did not live in poverty, so was lucky in many ways. On the more negative side, I was 'different' from my contemporaries due to these issues, and we didn't have the compensatory technology in those days.
What it didn't affect long-term: My academic attainment; my job performance; my ability to mix with others and make friendships,
What it did affect long-term: Permanent health anxiety, which is affecting me a lot now. Permanent guilt about possibly harming others, as I once feared causing my dad to become ill.
Well, that's anecdotal about one person! But I do sometimes think that people exaggerate the likelihood of permanent damage from being deprived of certain academic or social experiences at a specific age. For most things, there is not a critical age when one has to learn things or one never will. So long as children have normal exposure to speech and language; opportunity to form attachments to parents and carers; and are not exposed to extreme early trauma, they are likely to be able to function as adults, after coming from a wide variety of backgrounds and experiences. For instance, some countries start school at 4 and some at 7, and it seems to have little effect on ultimate outcomes.(I am not talking here about the too-common situations where lockdown causes or exacerbates poverty or abuse.)
On the other hand, I think that people perhaps underestimate how much children pick up on the dangers of the virus itself; the fear of losing parents and other relatives to it; and the guilt of real or imagined transgressions that might cause illness in themselves or others. I think the current generation of kids may grow up with a tendency to both health anxiety and guilt-proneness.
But no one really knows now. No doubt there will be a lot of studies in the future. It also depends on how soon the pandemic ends, and how much it affects both population health and the economy long-term.