I’ve never heard puberty described as making kids “a lot less social”, so not sure where you’re getting that from. A source would help your argument.
As someone who happened to hit that inflection point at the summer after high school I consider my cohort extremely lucky.
Hide in room, grunt when asked questions, moody, "disrespectful to their elders", that kind of thing is all "less social".
Although I can think of one specific context where I would say "shy" for a bit: suddenly developing a new axis of emotional drives (lust) that they have to learn to navigate socially.