My oldest is 10 and oldest daughter is 8, so we're approaching this challenge. We've talked to them in a broad sense about the issue, but your post made me realise that tackling it together is worth a shot. e.g., lots of talk about what the issue is, and what opportunities there are to address it. And then work together to devise a strategy. Not just them saying to peers "My parents say I'm not allowed to do x."
> Not just them saying to peers "My parents say I'm not allowed to do x."
Yes, that's the core of it. Working together on facing the issue while supporting increasing the agency of the child.
Anything forced onto them is just an external force to deal with. A decision made together, with own interest and long-term vision in consideration, with rules derived from these goals, are a very different thing.
One trains the child to submit + secretly subvert, the other nurtures trust and trains collaboration, openness, iteration etc.