I think that the best way for Apple to conform to all those regulations would be dual-tiering the iPhone (which I know they avoided for years) in software or even by two box designs. One would be "casual" iPhone (called just iPhone or iPhone Family), that'd have all the safety warnings, walled garden exits notification etc. etc., and then there would be "expert" edition or whatever, where there would be minimal notif…
This is the idea I've liked the most, require plugging into Apple Configurator or Xcode to put the device into developer "beware all ye who enter here" mode which forces a wipe. I've never heard of anyone casually unlocking their bootloader on Android, which requires a similar process. You'd lose most people once you said "plug it into a computer", and everyone who isn't a dev once you said "wipe the phone".