This type of delay is often caused by background activity restrictions, battery management, Google Play Services, or a system notification issue, especially when it happens on both Wi-Fi and mobile data. Since battery optimization is already disabled, check whether Background data is allowed for the affected apps. Also make sure Data Saver and Do Not Disturb are disabled. Restart the phone and update OxygenOS and Google Play Services. If multiple apps are delayed by 10–15 minutes, rather than just one, the issue is more likely system-level. You can also reset network settings. If the problem continues, testing in Safe Mode can help identify a third-party app causing the delay.