Not getting notifications after I did the iOS 13 update

I also had this issue after pairing my new iPhone 11 to my existing Apple Watch. Would receive notifications for text messages and phone calls, but nothing from any third party apps. I tried every solution suggested, toggling on and off different settings on both my phone and watch, I tried restarting the watch and phone, reconnecting Bluetooth/cellular, reinstalling apps... nothing seemed to worked.

Finally, i decided to unpair my Apple Watch (but kept my data plan)

instead of pairing through “backup” i started a “new watch” setup.

took a little time to get my apps and watch faces back the way I wanted but the watch is receiving notifications perfectly now

hope that helps

See if this helps....https://www.payetteforward.com/not-getting-notifications-on-apple-watch-heres-solution/

If that doesn't work, try this, unpair the watch and start pair again. Then you will get all notifications.

I had the same problem (no notifications on Watch after update).

I unpaired the Watch in the iPhone app, then paired it again.

That resolved my problem.