IPhone 12 Pro not receiving any notifications

Hi!

I have been using IPhone 12 Pro for a couple of months now but there is a problem with the notifications and it's driving me mad.

Since I got the IPhone I have been experiencing troubles with receiving notifications from all of the apps - Viber, Whatsapp, Telegram, Messenger, etc. When I open an app, I see that I got a message but I never received the notification.

All of my settings are correctly set, I have read tens of articles and couldn't find a proper solution.

I see that a lot of people are having troubles with their IPhones as well and there was an article related to that problem and somebody had commented that this was an Apple issue that they refused to fix.

Is that right or is there a way to fix this as this phone is my work phone and I cannot do my job with this issue.

Thanks for any help and suggestions!

PS. The IPhone is with IOS 15.2 and this problem started with IOS 14 or 13 (not very sure).