We give our kids zero direct acces to the Internet.
When they turn 14, we give them a locked down DeGoogled GrapheneOS kid phone that has no no web browser, no social media, and no Internet access.
As for measuring apps, they only get the apps that they need for church or school activities. If the apps give our kids backdoor Internet access, they don't get that app. We host our own Nextcloud Talk messaging app for or family chats. That keeps our family data private.
We even self host our own phone tracker for the phones out of our basement so we can all see where everyone is at any given time.
