As much as I'm not a fan of their products, there is very little you can do to help users when they (by proxy in this case) ignore or avoid your attempts to help them.
Making the option easier to find after on-boarding might help, but for the users you describe it would need to be very easy to access and you will fill any list of quick-access options very quickly if you include things they may only want to use one or twice in the life of the phone rendering the "quick access" a big scary list that is neither quick nor easy. Even if you do find a good place for the option: will that class of user even know to look for it never mind find it? They'd just ask the person who on-boarded them instead so the technical level of the target audience has changed back to someone who at least knows how to Google for where to find a more buried option.
So don't ask them. Default to a non privacy invading mode. Ask the questions later of people who wants the features.
I don't buy "this is the pinnacle of ease of use" and we can't get further.
I know many people (yes, most of them older) for whom the idea of trying to look at an unfamiliar process on a computer (including smartphones) and see if it's something they can do themselves is just a completely alien idea. If it's not something they're already familiar with, it's Scary Technology Stuff, and they need a Technology Person to handle it for them.
It seems a bit of a stretch to ask everyone around me to drive go there every time they get a new phone.
Reality: people who feel that they need help, and for most features it's a one-time trip with settings passed from phone to phone as you upgrade.
And of course there are still countries where there is no Apple store, but you see quite a few iPhones.