Good comparison with a digital swiss army knife, we use our phones in so many ways.
With kids it's very complicated, my teenagers are a bit younger (12 and 13) and I don't want to invade their privacy too much but I do want to keep them safe, talking is indeed my solution as well and hoping I teached them enough about the dangers, it's also important for them to be able to make mistakes.
I'm not even having a big phone addiction, more of a PC addiction due to splinterlands and everything around it, like you I decided to change that when it got too much 👍😁