I had the same a you. iPhone 8 plus with iOS version 16.7.8
Since yesterday no more notification from my cameras - doorbell - messenger - WhatsApp - messages.
Got only notification from mail.
I did everything what was mention on google by users, by Apple support, nothing helping me.
And I didn't wish to do a reset, because all my logins and passwords went away.
So today what I did, as test !!!
I removed my app from the cameras
Went on app store and re-install it again.
Loged in in the app from cameras, and did the test to go outside to the cameras, and Yes I got again the notifications.
So i removed Messenger - WhatsApp and messages and doorbell apps. Reinstall them again, and got all the notifications again from all the apps.
Hope it will help you
Greets, Gene