Assuming age ID wasn’t invasive and stupid to begin with, there could be other ways to set it that would be much less invasive for many devices, such as setting an “IS_ADULT” flag on devices (or even an associated account) at the time of registration.

“Hey Mr Smith, it looks like you’ve never registered a device on our phone network before but you’ve got a driver’s license from 1979 so we’ll just set the age code on your account aaaand, done”.

Then you get a sheet of random scratch-off AV codes pulled from a drawer that you can use on other shit, similar to how VPN providers do to separate payment vs login. Nothing should ever say who you are or even your age, just “hey this person is old enough, fuck off and let them at it”.

It’s still annoying, but less privacy invasive. And it’ll never fly because what they really want is to tie all communication back to a person not just an age.