I am not receiving push notifications on my iPhone after iOS 18 update

The only thing that worked for me was resetting all settings. Settings app > “General” > “Transfer or reset iphone” > “Reset” > choose “Reset all settings” from the popup menu.

It’s annoying that it requires a blanket fix like that, but it’s way less frustrating than the notification problems. The most intense implications of resetting your settings, in my experience, was that every app acts somewhat like a newly installed app when you open it again after resetting – it’ll keep your “in app” settings (so any settings you’ve managed from the app itself isn’t reset) and data (it doesn’t wipe your app clean), but any settings in the literal iPhone Settings app will be set back to default values. This means you have to allow camera and mic access, access to photo library, access to your location data, etc. I found it a nice way to kind of overhaul my privacy settings everywhere, silver lining.

please note that it will also delete your saved Wifi passwords, unless you have them saved in the passwords app like your network is a website (the passwords app is safe from the reset).