Maybe instead it is the school that should change and adapt to a world where everyone is assumed to have a phone.
These days, more and more do I perceive internet-connected smartphones as an adult temptation which children needn't be exposed to. Yes, they live in a world where most people have phones. They also live in a world where most people drink! It will take some time and it will be uncomfortable, but I'm of the opinion that a slow, society-wide shift away from all-day children's device usage is what's needed to stop the bleeding.
When I was in high school 99-03 you couldn't go into the bathroom without seeing someone smoking a cigarette or a joint, I even had a teacher that would let you have a restroom pass under the condition he reserved the right to smell you (at a reasonable distance) when you returned to make sure you didn't smoke. Now kids try to sneak vapes in class (my wife is a high school teacher) and at a school she taught at before we got married they had a student OD on fentanyl that someone had laced his vape cartridge with.
When I was in high school you'd have kids on MDMA in class too with some regularity.
A friend that is also a teacher, about 7-8 years ago, had (presumably) a student dose her Starbucks sitting on her desk with a roofie which required her being in the hospital for 2 days. Schools aren't doing a good job of anything in that regard. Even prisons can't keep drugs out and they have strip and cavity searches.
I’m not sure the way a school should adopt to the world is to allow every kid to legally carry a gun.