By high school there is definitely an expectation that everyone has a phone. They will literally miss out on a normal method of communication between friends and classmates.

They miss out on the social group and then fade away from it and just become "that one guy in our class."

The last time I mentioned this several people argued that, "true friends would stick together" or some such. Well, if you already have those friends. But if you're in high school and finding yourself, you probably haven't met all of them yet.

A lot of both communication and organizing of social events happen through the phone. Kids without a phone (or some online method) will just be forgotten. This is just the reality.

Unrestricted access? That depends on the kid. We had them charge in the living room (no overnight use), and their computers were actual desktops in a single office in the house.

We never used filtering or tracking software. The one exception was blocking youtube (through /etc/hosts) for my youngest during covid when it was too big a distraction.

This is just generally true even as an adult. A lot of social events used to start out on text threads in the early 2000's and then moved on to Facebook Calendar by the mid 2000's and then Instagram and I don't even know how it would work now. But if you wanted to be in any particular social group you probably had to deal with the icky features of all of these social media apps just to do that. We needed a public square for our little villages everywhere and instead we got a man screaming at clouds and occasionally handing out invitations.