I think you're putting too much emphasis on The Algorithm. It's a problem, and I agree it's probably the worst offender, but similar problems were observed decades ago with children (and adults...) allowed to watch too many hours of uninterrupted TV. Cutting back to chronological feeds might improve some things but I don't think that's the root of the issue.
I would suggest the primary difference between then and now is accessibility. As a kid, my screen time was limited not just by my parents indulgence but the social pressure from using a shared device. Smart phones let you carry your personal distraction with you.
I agree they are a wonderful invention but I'm not sure grade school students need to be connecting to anyone, anywhere throughout the entire school day.