Why Messenger still works even after I disabled its network permissions?

Actually sometimes I want to use the internet on Android but don't want to get the notifications from the social media apps like WhatsApp, Facebook, Messenger Instagram, Telegram etc. So what I tried to do was the following settings on my Android phone (Oppo A5 2020): Setting -- Sim card & Mobile data -- Data usage -- Network permissions And then find the required app and disable its network permissions and disable the network permissions completely. My Question is That: Why I still get the notifications from these app? Although when I open the app, it asks me first to allow the network permissions. For example, when I disable the network permissions for Messenger, and after that, If someone send me a message on messenger, I will get the notification (with message showed in the notification bar) and when I click on the notification, it will lead me to messenger app. But As I opened the app, I see the notification: "Network is turned off for the messenger. You can modify it in Settings - Sim card & Mobile data - Data usage - Network permissions " First I thought it might be because Facebook is connected to messenger, so only disabling data access to messenger will not be enough for Messenger to stop sending the notifications. So I tried for both Facebook and messenger, I still get the notifications from messenger and Facebook, then I thought Instagram is also linked to Facebook, So I disabled the data access to every single app of Facebook in my Android, but still I get the notifications. Can anyone know why is that so? **Note: ** As I know I can mute notifications for chat from every app. But in this Question, By not getting notifications means I want the person who is sending texts me on social contact forms like messenger and WhatsApp that the message is not yet delivered to my Android phone. For Example: If someone send me a message on WhatsApp, I don't want the double tick in his mobile.