Location services and what both iPhone and iCloud do with that data are two different things. Also, after a major update, you get a list of steps to complete, as the iPhone needs to get reactivated. I just did the for in iPad I updated to 11.
What dialog box? iOS itself has only a few ones that pop up in a while. Like re-authentication with your app store password, though that’s rare.
The only other I’m aware of are the access permission, which get triggered when an app wants to access data where they may be privacy concerns. Like accessing the camera roll, location data, contacts. It all started with location data, the other came later. You need to answer those dialogs only once or twice. They appear when the apps are on the screen and active, so not while you are dialing. The only exception for these app-triggered dialogs I’m aware of is the background location tracking.
That one didn’t even exist in iOS 5, AFAIR. Came later with 7 or 8. When an app uses location tracking while in a background, iOS would notify you 24 hours later or so, when you using the device, so to remind you to check if you really want this. That dialog comes once per app.
What does happen more is annoying non-Apple app send you timed reminders to buy loot boxes, make your journal entry, etc, what basically amounts to “hey! I’m here! Notice me! Use me!". More apps, more services, more notifications. You get a dialog from iOS allowing or disallowing those once, though. So disabling them right on the start is quite possible.
I thought you went back to a brick phone?