I wouldn't ban them entirely, if only because cell phone calls to emergency services have saved many a life.
But the current app ecosystem really isn't there to serve the phone owner, tbqh.
On phones, disallowing certain forms of predatory behaviour like malvertising and addictive engagement algorithms might be an early quick win. The utility of your phone might actually improve!
I'm sure it's bad for adults as well, but school aged kids are in their formative years where learning how to talk to someone in real life is a skill that needs to be developed. Their brains are also not yet fully developed, so their time should be spent learning. Not fucking around in class on tiktok.
I was a student at one point myself and also wasn't able to use my phone in school. Boo-hoo? It's a bit like being a kid and complaining to the adults in the room that they don't let you smoke and drink.