Not sure why this is downvoted it's a common opinion and one I've also thought about a lot. I am actually about to do it, I think it's actually trivially easy

Not sure why this is downvoted it's a common opinion and one I've also thought about a lot. I am actually about to do it, I think it's actually trivially easy if you give up on the phone number being the same for voice calls. If you have two iPhones then you can still get iMessage on both. And like who needs voice calls. If you really care you could forward one to the other. The "dumb" one you set up MDM on and disable the browser if you want to really mean it. Just have text messaging, Kindle, spotify/music, and google maps. Seems like a decent compromise.