I'd argue you don't need a study, just reasoning. I mean, a study would be good, but we also have brains on our shoulders.

Learning to read or to do mathematics is like anything else, it takes practice. We know, intuitively from our own lives and observes virtually all humans, that humans perform better with less distractions. It would be hard to learn how to play the Tuba with me screaming behind you. It would be hard to learn chess with a movie playing in front of you.

Phones are distractions. Less phones = less distractions = better performance, smarter kids, more likelihood to graduate, higher average income.

I'd link to some of the many studies published by reputable sources, but I suspect you'll brush them aside with your caveats

That 'caveat' is the actual science. So it's a pretty big deal.

More meaningless words that can be defined as needed by you to support your rather bizarre agenda.

Numerous peer reviewed articles published in reputable journals have reported that there are advantages to banning cell phones in the classroom, yet you as the sole arbiter of "actual science" declare otherwise.

We don't actually need "actual science" to conclude that phones in classrooms are likely causing problems. We can observe them in action causing problems and take actions even if the peer reviewed double blind study hasn't been done

Actually, we do. That's kind of the entire point of science.

We have to make the best decisions we can with the information we have

The point of science is to provide better information for us to make decisions with, not to prevent us from making decisions at all until it's done

If we waited for science to settle and provide the best information possible, we would never get anything done