This is the way to go. I don't have kids, but it's how my sisters went about it. For the longest time if my nephew wanted to call and talk to me, the number would ring up as my sister's number, because not only was it a spare phone, but it was dually connected with her number (not sure how tbh, she worked for a carrier for a long time).

It's just hard to find that thin line between allowing them to have something or have them be behind all their friends who do have access to one.

My policy would probably be worse, tbh. I'd toss them an old Nokia and be like, "Legends say it'll take the force of an 18 wheeler and a flood and still work." For context, I had a friend who ran his over 3 times with his dad's mack truck, reducing it to just a screen and PCB which he used as his phone at school. Then I watched him accidentally drop and fully submerge said screen and PCB into a half foot deep puddle while we ran down a mountain in a thunderstorm and that sucker still worked.

It was his experiment, to keep trying to destroy it to the point where he couldn't use it but have to use it if it did. I think it died not too long after, though.