I think I'm lucky as my kids aren't in really essential years (start of primary, secondary exams) and both schools are mounting a fairly good provision online, especially the secondary. And TBF, we are a very fortunate household where the kids have space and equipment to learn. Even with DS (Y5) having ADHD, I don't feel as though either of them will underperform academically in the long run because of this.
Emotionally/socially I have more concerns for what they've missed out on, especially with DS having some challenges to managing social skills, and DD missing out on chunks of her first and second year of secondary school - I feel that chould have more of an impact for them than missed learning.