Capacitor push notification guide gave me an error

For the Capacitor guys.

I tried to use the new push notification guide for iOS but it didn’t work.

I ended up using this guide by Simon Grimm and it worked.
It is similar but it uses Firebase rather than FirebaseCore and does not add FirebaseCore to the Podfile.
I have no idea what the difference is.
https://devdactic.com/push-notifications-ionic-capacitor/

See: