Thanks for your reply. I do the things you suggested, but there comes a point when you urgently need to open an app like camera and can't do that because there is not sufficient storage.For these emergency situations, there must be an option to keep ...

It's more than an year, and the same problem continues

Exactly, the notifications are scattered all over in the notification panel, especially for the apps like Instagram and Facebook. It's such a turn off and reduces the productivity, spoils the experience!