I have an 11 (y7) & 14yo. They had tablets for games in the junior school years with tight parental controls. They were given mobile phones Christmas y6 so they were accoustomed to them before y7. They were among the last of their peers. Many got them younger as the only way to socialise legally during lockdowns- a depressing reality of that specific age group.
Ds1 isn't socially motivated which makes life simpler. He likes factual documentary content on youtube. I have a decent idea of what the algorithms offer him because he mainly watches on a large compter monitor and I can see the content when I come in the room.
DS2 uses whatsapp to communicate with close friends. He had those two terms in the relative safety of primary school (at least there was a parents' Bat Signal if things were going awry) to learn that large chats are a waste of time. I do monitor it, and fortunately at this point in time he has sensible taste in friends. Again from watching youtube on the main TV, I have a decent idea of what the algorithms put his way.
I have aways talked to them and encouraged them to me if they see anything that makes them uncomfortable (especially if they did something daft)
I've talked to them about why apps like Tiktok and Snapchat are problematic and why I won't authorise them. They are happy with youtube and whatsapp with light monitoring.
It's not foolproof, but phones and social media are integral parts of society and aren't going to be put back in the bottle. Childhood is about gradually learning and building up the skills of adulthood. Keeping them in a bubble until a magical age (like 16) and hoping they've automatically matured past some pitfalls doesn't necessarily equip them with the skills that they need.
Phones are essential tools of independence. I can't pretend it's 1995 and that phone boxes are plentiful and a 30p bus fare will cover their needs. Society evolved. Access to google maps was invaluable for DS1 last year when the bus route was diverted through areas he doesn't know when trees were blocking roads during a storm.
DS1 is more technically minded and savvy than me. I'm better working with his good will than encouraging secrecy!
I'm glad younger parents are getting more switched on. Delaying and managing access as long as is viable is sensible, but I don't think abstract bans to absolve parents from parenting is the answer. Knee-jerk reactions often cause more problems than they solve.