Phone use during class time is banned in my kid's high schools.

Makes no difference -- it's completely unenforced by the teachers. They're practically physically adults, teachers don't want to risk the confrontation, etc. And the kids suffer for it.

And my youngest uses no social media but their mind is still eaten by constant phone usage.

More than social media, the problem is the device. The form factor.

The "smartphone" is a malevolent technology.