Notification setting not showing

My friend just bought a brand new iphone 16 and notifications for some apps are not working. I tried if other settings were on like Do not disturb or something and there was no problem there. As the instagram app showed "set notifications from your device settings to get updates" it meant that permission is needed but, the pop-up when you first install the app whether you are turning the notification or not isn't showing. He re-installed the app for like 7 times. And in the Settings - Apps - Instagram, the notification toggle is gone. Like it's not there. Even in Settings - Notifications the Instagram app is not showing up. As an apple fanboy and receiving several questions from my friends, I've never seen something like this.