My phone is my agency. I use it to access information, and to communicate.
Why on earth would you subject yourself and everyone you know to arbitrary limitations like that?
My mind is plenty free and I use the tool when the circumstances warrant, and not as a mental fidget spinner.
And before you say that it’s the apps you choose to install, not the phone that’s the problem, I’d say that’s a distinction without a difference.
Also, it is possible to make phone into useful tool. I make audible/vibrate notifications for important things so don't need to check phone constantly. Put the phone down and only use it when you need it. Try moving content consumption to another device. Try limiting addictive things to certain circumstances.
If that doesn't work, consider deleting the addictive apps and turning the phone into a tool. Smartphone without addiction is more useful than a dumb phone.
My phone is a nice-to-have. Its primary use is navigation and photography.
I could survive fine without it.
Why on earth would you subject yourself and everyone you know to arbitrary "agency" like that?
Me too (mostly), but I don't think everyone has that much willpower.