Notifications Issue

Hello everyone. I have an iPhone 17 running iOS 26.3 and since day one notifications are delayed for several minutes, and sometimes I don’t receive notifications from apps like WhatsApp, Instagram, Reddit, etc until I unlock the phone.

I have tried:

1. Turning off Apple Intelligence features like notifications summary and priority.

2. Deleting “Reduce Interruptions” focus.

3. Checking background app refresh.

4. Checking notifications settings for all apps.

Nothing seems to solve the problem. Can someone help tackle this issue please.