Look at something similar to...
Settings - Display- Led Indicator.
Turning this on should then make the led indicator light up for unread notifications.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.
The J3 doesn't have an LED, but I've heard there are apps that can approximate one. I was hoping this thread would have a recommended one. Does anyone out there know of a good one?