Fix Surf Forecast App Notifications

I have a surf forecast app (React Native / Expo) and the notification feature is not working properly. I need a developer to fix it.
How it should work: the user sets a time, and every day at that time gets a notification with the surf summary for their spots. Tapping the notification should open a screen in the app showing that day's conditions.
The current problems:
The notification arrives late, a few minutes after the scheduled time
When the user taps it, the app opens but shows nothing, no summary appears
It does not work when the app is fully closed
On iOS it is especially unreliable
So right now the feature is basically unusable. There is already a backend that generates the summaries, and the app also uses a third-party push service for other notifications, which may be part of the conflict. I am open to your proposal on the best way to fix it, so in your bid please tell me how you would solve it.

To close the job I need:
1. The notification arriving on time, on both iOS and Android
2. Tapping it reliably opening the summary screen with the day's data, even from a closed app
3. A short video showing it working on a real device, iOS and Android
Looking for someone with real experience in React Native / Expo and push notifications, especially getting notifications to work reliably when the app is closed.