Physical keyboard? Notification LED?
OLED displays have obsoleted notification LEDs. And phones with physical keyboards don’t sell.
OLED displays certainly could, but there is no baked it app that wakes up the screen only if you have a message, blink in different colors or frequencies depending on the message and use the low power always on display api.
Yeah, you can glance at your always on display and make out the little symbol. But that’s not an adequate replacement to the notification LED. If I had to guess, it was removed to drive up engagement with your phone.