Bell to Bell bans are fine in my honest opinion.
I do not acknowledge the mandate that all children must have constant access to their phones. Students who have a legitimate reason to carry their phones on their person at all times should be supported by their parents with a request to the school administration. School admins who receive such requests by parents should accept them with no questions asked, and only confiscate the device from the student if they are found to be misusing it or disrupting a class with it; no "If I see it; I snatch it" rules are to be allowed.
If schools have to issue "Phone-allowed Hall Passes" constantly; it disrupts class. If a student can be issued a personal pass that discloses they're allowed to keep their phone on them, per parental request for a legitimate reason, think medical reasons or reasons related to disability and note taking, there's less interruption if a student needs to make a critical phone call to get help.
I do believe schools should provide and encourage device storage. Students of appropriate ages should be allowed to access them in storage during break times. Teaching students the ability to self-disconnect from their mobile devices is important. This can be done efficiently and without cruelty. Responsible students with fewer phone infractions can be permitted to carry their phone more often or during wider hours of the day; while those who do misuse their phones or disrupt classes with them can be forced to keep their phones in storage from bell to bell as the law suggests.