Apparently by Design, iPhone SE Owners Cannot Use Haptic Touch Features With Notifications ⇥ macrumors.com
Juli Clover, MacRumors:
With Haptic Touch-enabled devices like the iPhone 11 and 11 Pro, long pressing on a notification in the Notification Center or the Lock screen brings up interactive options based on the app sending the notification. An Apple News notification, for example, brings up options for reading the full story, sharing a story, or saving for later, while an email app might offer options to reply and delete an incoming message without needing to open the app.
In our testing, we were not able to long press on a notification to view these interactive options, as the long press functionality did not work. We also tried on an iPhone 8, which the iPhone SE is based on, but we were able to get the rich notifications to work on that device, which has 3D Touch.
This is such a bizarre and seemingly arbitrary limitation. There is no reference to it in the iPhone user guide, and it is the only iPhone model with either 3D Touch or Haptic Touch where this specific interaction and no other is not present.