Young teens who experience an edgy phase are a good thing to have. It’s a symptom that they realise value systems should be inspected. Being edgy might just be a by-product of realising that they’ve been taking things for granted.
Instead of living out what other people have told them to do, they are beginning to realise that they don’t need to. Which sounds like what teenage rebellion is about. And of course some things are actually important, and rebellion for rebellion’s sake is not that helpful.
Also, being nihilistic is a natural conclusion to realising that many things are constructed.
But it shouldn’t end there. The hope is that they move on to actually deciding what matters. Like the realisation that happiness is actually something that is hard-won, and not just the product of ignorance among your peers.
It’s one way to have engaged people who seriously consider their goals. Much better than sheep who never question their actions.