Re: “… you are completely wrong … “
No one asserted that it was — or wasn’t — “related” to the update.
However, carriers DO have developer teams who work to ensure the continued functionality of their own various on-device carrier apps in advance each iOS update’s roll-out.
These updates are normally pushed out immediately after your iOS update
completes; with the screen briefly displaying “Carrier Update in Progress”.
As with most such things, sometimes technical glitches prevents these updates from being automatically pushed out; or from being properly applied on the phone.
Sometimes the developers — being human — might have simply overlooked a particular aspect of the update.
Regardless of the cause, resolution requires reporting to, and working with the carrier to resolve.