Delays with notifications are typically attributed to signal connection strength ,and or network congestion @niikez
You could try clearing the cache of the app by long holding the app icon and tap on the i and then choose storage and clear Cache.
Double check the permissions the app has been allowed.
If I can be of any further help then please don't hesitate to ask. 😎
Daily Driver > Samsung Galaxy s²⁴ Ultra 512Gb ~ Titanium Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
