I agree about the electromagnetic pulse!

Yes you've made good observations about not needing it 24/7. We've been quite "strict" about use of phone/laptop in our house. The rule has been no devices in your bedrooms until you turn 18 and phones got handed in at 7pm and laptops as soon as you finished homework (though "home work" often dragged on and on). She was excited to turn 18 and have more privileges but we've had conversations with her that she needs to be more stable to keep her phone etc all the time.
So in the country where we live, you buy bundles of credit to load on the phone as opposed to paying a set monthly fee. For example, we buy her a bundle for about $10 that gives a certain amount of GBs data plus number of texts and phone calls. It lasts for a whole month because she uses wifi most of the time.
I've also considered putting an app lock on all apps so she can only access her anxiety games, phone calls and texts but not go online directly. Problem is those apps tend to be pretty easy to get around - you can even just uninstall them without needing the password to do so.
Do you ever just get tired? It's tiring work having to constantly come up with solutions and manage the current crisis.